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I'm doing my homework and after missing school for 3 days due to being very sick I need some help, bad.
We just started basic algebra and now we are getting into the harder parts. I assume TL can help me because many of you passed college or are already above a 9th grade education. (I'm in 8th grade but I'm taking pre ap so its pretty much 9th grade work.)
So TL, I am asking you to review my work and tell me my errors, I also ask that you show me how to check my work. Because if I can check correctly I will never get a problem wrong, the thing is I do not know how to check my problems...
Ok for problem number one it is :
5p - 9 = 2p + 12
So what I did here was add a plus 9 on the left side to even it out and added a 9 to the 12 because everything I do to one side I must do to the other, right? so now my problem is
5p = 2p + 21
What I did now was I subtracted 2p from the right side and added to the left so now it is
7p = 21
now what I think I need to do is get the p all alone, so I would have to multiply but we're doing inverse operations so I should divide it, so now I basically end up with p alone and I see how much times 7 goes to 21 and of course that is 3...
now I have p = 3 basically and I know that is right I just need to learn how to check it. Can someone here on TL please tell me if their are any flaws in my math and tell me how to check it?
  
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5p - 9 = 2p + 12
5p = 2p + 21
3p = 21
p = 7
Edit: Check by putting p back in and seeing if the two sides are equal.
5(7) - 9 = 2(7) + 12
35 - 9 = 14 + 12
26 = 26
So p=7 is right.
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You just substitute 3 into the original equation as p, and if both sides are equal than you're right.
So, 5(3) - 9 = 2(3) + 12
15 - 9 = 6 +12
6 = 18
WRONG.
Try again:
5p - 9 = 2p + 12
5p = 2p + 21
3p = 21 (this is where you messed up, you added 2p instead of subtracted)
p = 7
5(7) - 9 = 2(7) + 12
35 - 9 = 14 + 12
26 = 26
CORRECT. Done.
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motbob
United States12546 Posts
+ Show Spoiler +Birthday: May 06, 1990
??????????????
You have to subtract equally from both sides of the equation, because if you were to add 1 to one side and subtract 1 from the other side, the two sides would no longer be equal!
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I LOLed upon reading the title
Well anyway... you can't add 2p to one side and subtract it from the other. You have to do the same things to both sides. So you get 3p = 21
And 3 is not right, and checking that is as simple as plugging 3 into your equations. 5(3)-9 = 6, 2(3)+12 = 18, 6 =/= 18.
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On October 14 2009 09:38 motbob wrote:+ Show Spoiler +Birthday: May 06, 1990
??????????????
Its fake.
And thanks for everyone correcting me, ty very much =D
Yeah I see what I did there.
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United States4991 Posts
On October 14 2009 09:34 Monstah-_- wrote:
I'm doing my homework and after missing school for 3 days due to being very sick I need some help, bad.
We just started basic algebra and now we are getting into the harder parts. I assume TL can help me because many of you passed college or are already above a 9th grade education. (I'm in 8th grade but I'm taking pre ap so its pretty much 9th grade work.)
So TL, I am asking you to review my work and tell me my errors, I also ask that you show me how to check my work. Because if I can check correctly I will never get a problem wrong, the thing is I do not know how to check my problems...
Ok for problem number one it is :
5p - 9 = 2p + 12
So what I did here was add a plus 9 on the left side to even it out and added a 9 to the 12 because everything I do to one side I must do to the other, right? so now my problem is
5p = 2p + 21
What I did now was I subtracted 2p from the right side and added to the left so now it is
7p = 21
now what I think I need to do is get the p all alone, so I would have to multiply but we're doing inverse operations so I should divide it, so now I basically end up with p alone and I see how much times 7 goes to 21 and of course that is 3...
now I have p = 3 basically and I know that is right I just need to learn how to check it. Can someone here on TL please tell me if their are any flaws in my math and tell me how to check it?
You did not do it right  When you subtract 2p from the right side you also need to subtract 2p from the left side, not add it to the left side. That goes with what you said before, where "everything I do to one side I must do to the other"
To check the answer you get, replace every occurrence of p in the original equation with the answer you got, and then work out what each side is equal to. They should be equivalent.
edit:
ffs, million people post in like 7 minutes.
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Ok, TY very much everybody! I think I'm one step closer to getting a 95+ in math =D
Now to do equations with fractions.. expect another thread in a short amount of time or this OP edited..
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motbob
United States12546 Posts
On October 14 2009 09:43 Monstah-_- wrote:
Ok, TY very much everybody! I think I'm one step closer to getting a 95+ in math =D
Now to do equations with fractions.. expect another thread in a short amount of time or this OP edited..
second option would be better
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Wait, this is eighth grade work? I'm pretty sure you learn basic algebra in 6th grade.
Fractions shouldn't be much more difficult, just multiply by a common multiple and you'll end up with clean integers to work with.
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On October 14 2009 09:47 Loser777 wrote:
Wait, this is eighth grade work? I'm pretty sure you learn basic algebra in 6th grade.
Fractions shouldn't be much more difficult, just multiply by a common multiple and you'll end up with clean integers to work with.
I'm pretty sure we will get into 9th grade work lol.. this is just starting us off, the teacher said we will have to do all this crazy shit. At first we started off drawing models and he said we gotta work our way up to the higher shit so yes, I think this is 9th grade work..
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This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[
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For fractions (like 1/2x), you just multiply both sides by the inverse of whatever fraction of x you have.
For example 1/5x = 4
(5/1)1/5x = 4(5/1)
5 times 1/5 is 1, so you're left with x = 20
This is probably confusing you, I'll just let your teacher do it :/
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motbob
United States12546 Posts
On October 14 2009 09:53 BlackJack wrote:
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[
??? I didn't learn algebra until 8th grade, and most high schools have Algebra 1 as the standard freshman high school math course.
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On October 14 2009 09:52 Monstah-_- wrote:Show nested quote +On October 14 2009 09:47 Loser777 wrote:
Wait, this is eighth grade work? I'm pretty sure you learn basic algebra in 6th grade.
Fractions shouldn't be much more difficult, just multiply by a common multiple and you'll end up with clean integers to work with. I'm pretty sure we will get into 9th grade work lol.. this is just starting us off, the teacher said we will have to do all this crazy shit. At first we started off drawing models and he said we gotta work our way up to the higher shit so yes, I think this is 9th grade work..
Oh the crazy world of fractions
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On October 14 2009 09:55 motbob wrote:Show nested quote +On October 14 2009 09:53 BlackJack wrote:
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[ ??? I didn't learn algebra until 8th grade, and most high schools have Algebra 1 as the standard freshman high school math course.
yeah this shit was hard when i first learned it in 9th grade
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On October 14 2009 09:55 motbob wrote:Show nested quote +On October 14 2009 09:53 BlackJack wrote:
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[ ??? I didn't learn algebra until 8th grade, and most high schools have Algebra 1 as the standard freshman high school math course.
depends. i didn't learn algebra in school until 8th grade but i learned it from my parents way before
and man. i wish my AP calc class had stuff this easy
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Osaka27174 Posts
Keep it all in one thread please. You may also want to brush up on your beginner spelling. :p
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I learned algebra in 8th grade as well
?_?
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On October 14 2009 10:11 Manifesto7 wrote:
Keep it all in one thread please. You may also want to brush up on your beginner spelling. :p
rofl. mani and his words of wisdom.
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yeah, algebra in 8th and geometry in 9th. i STILL hate geometry proofs. so annoying
i miss 8th grade math D:
edit:missed a word.
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Yeah this is 8th grade stuff...not 5th rofl BlackJack. Kind of funny to see though, I forgot that there are probably some kids on this website.
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On October 14 2009 10:12 FragKrag wrote:
I learned algebra in 8th grade as well
?_?
On October 14 2009 10:00 arb wrote:Show nested quote +On October 14 2009 09:55 motbob wrote:On October 14 2009 09:53 BlackJack wrote:
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[ ??? I didn't learn algebra until 8th grade, and most high schools have Algebra 1 as the standard freshman high school math course. yeah this shit was hard when i first learned it in 9th grade
On October 14 2009 09:53 BlackJack wrote:
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[
Yes, this is learned in 8th grade, Arb and BlackJack just think that they are cool for acting like they have a long internet penis when they really don't.
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On October 14 2009 10:25 Monstah-_- wrote:Show nested quote +On October 14 2009 10:12 FragKrag wrote:
I learned algebra in 8th grade as well
?_? Show nested quote +On October 14 2009 10:00 arb wrote:On October 14 2009 09:55 motbob wrote:On October 14 2009 09:53 BlackJack wrote:
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[ ??? I didn't learn algebra until 8th grade, and most high schools have Algebra 1 as the standard freshman high school math course. yeah this shit was hard when i first learned it in 9th grade Show nested quote +On October 14 2009 09:53 BlackJack wrote:
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[ Yes, this is learned in 8th grade, Arb and BlackJack just think that they are cool for acting like they have a long internet penis when they really don't.
Yeah im a Classy troll
But really i wasnt being sarcastic
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United States24784 Posts
As some have pointed out, algebra is not fifth or sixth grade material in the USA. It is usually done in 8th or 9th grade. I did it in math 8 enriched but this was a while ago when math was a little different.
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Ha I took algebra in 8th grade but I knew I could've been one more year ahead because there was this 8th grader I knew who took geometry... I took geometry in 9th grade, but some of my friends were taking algebra II and i was like, fuck this shit i don't want to be a noob anymore. so i took algebra ii during the summer at a community college with a bunch of 30-40 year olds (a real serious eye-opener for me) it felt weird being the youngest kid in the class but i rocked the shit out of it and got an A. Finally caught up with my friends and took pre-calculus in 10th grade.. IB Calculus in junior year.. and then calc II senior year. YAY.
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this kind of algebra is pre algebra
which is 6th grade in the US or at least thats when I/all my friends took it
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Snet
United States3573 Posts
I love how no one is like, "fucking hw thread", just because they actually know how to do it.
lol
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Roffles
Pitcairn19291 Posts
On October 14 2009 10:48 Snet wrote:
I love how no one is like, "fucking hw thread", just because they actually know how to do it.
lol
I'd be worried if someone couldn't do the problem in the OP.
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ok typically algebra 1 you take in 9th grade if you're in an average course. in 8th grade if you're in advanced courses, or in 7th grade if you're in a gifted program. But this is hardly algebra 1 work... Even in pre-algebra you should have already learned the order of operations and dealing with parenthises and exponents. Basic concepts like "what you do to one side you have to do to the other" should not be 9th grade work....... I was first exposed to this in 3rd grade but only briefly and more extensively in 5th grade. They may have done it in your schools and you just forgot as well, but they use 2 variables I think 1 is called a "star" and the other is something else, but they are opposites of each other so that one variable is basically X and the other is -X so that it teaches canceling out and taking away from each side very easily to break down the problem and get the solution.
Actually in 3rd grade it wasn't even done on paper, they just gave you a "scale" with the 2 different variables represented by small statues like white + black pawns from a chest set, and if you take a white pawn from the left side you have to take a white pawn from the other side. Or you can take a white pawn and a black pawn off the same side since they are opposites and cancel each other out. This is very very basic algebra, just like the OP's problem and it's not 9th grade algebra 1 iirc.
and yeah I probably came off as an ass, but that's only because I was 99% sure OP was trolling, especially since his birthday said he should be 19
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On October 14 2009 11:05 BlackJack wrote:
ok typically algebra 1 you take in 9th grade if you're in an average course. in 8th grade if you're in advanced courses, or in 7th grade if you're in a gifted program. But this is hardly algebra 1 work... Even in pre-algebra you should have already learned the order of operations and dealing with parenthises and exponents. Basic concepts like "what you do to one side you have to do to the other" should not be 9th grade work....... I was first exposed to this in 3rd grade but only briefly and more extensively in 5th grade. They may have done it in your schools and you just forgot as well, but they use 2 variables I think 1 is called a "star" and the other is something else, but they are opposites of each other so that one variable is basically X and the other is -X so that it teaches canceling out and taking away from each side very easily to break down the problem and get the solution.
If you looked at what I said on the first page this is just review at this time, I would be glad to tell you what I am learning halfway into the year.
We have learned to do everything you stated in 6th grade but I can tell you it was much different then this.
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17070 Posts
On October 14 2009 10:48 Snet wrote:
I love how no one is like, "fucking hw thread", just because they actually know how to do it.
lol
Actually I think it's because people don't want to be assholes to eighth graders :/
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Yeah Algebra is usually 8th grade, I was one of the lucky ones and got to take it in 7th grade..unfortunately,math/physics is all I'm good at in school..
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On October 14 2009 11:31 Empyrean wrote:Show nested quote +On October 14 2009 10:48 Snet wrote:
I love how no one is like, "fucking hw thread", just because they actually know how to do it.
lol Actually I think it's because people don't want to be assholes to eighth graders :/
Ehhhh I'm with Snet on this one.
The first reply answered it correctly, I don't see how this even got to two pages TBH. Many students learn different things at different times in different countries. Nothing to discuss/argue about really.
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On October 14 2009 10:25 aeroH wrote:
yeah, algebra in 8th and geometry in 9th. i STILL hate geometry proofs. so annoying
i 8th grade math D:
Same here. I'm in university, and I still hate the geometry I learned in high school. Scary stuff IMO >_<"
Also, depending on where you're from/what curriculum you're using, this material could be learned earlier/later. Enjoy middle/high school while you can!
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On October 14 2009 11:45 Chromyne wrote:Show nested quote +On October 14 2009 10:25 aeroH wrote:
yeah, algebra in 8th and geometry in 9th. i STILL hate geometry proofs. so annoying
i 8th grade math D: Same here. I'm in university, and I still hate the geometry I learned in high school. Scary stuff IMO >_<" Also, depending on where you're from/what curriculum you're using, this material could be learned earlier/later. Enjoy middle/high school while you can!
Geometry and Trig both. I hated working with them in my calculus courses.
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Agh, Geometry is my least favorite branch of Math. Even trig ranks above it.
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On October 14 2009 11:31 Empyrean wrote:Show nested quote +On October 14 2009 10:48 Snet wrote:
I love how no one is like, "fucking hw thread", just because they actually know how to do it.
lol Actually I think it's because people don't want to be assholes to eighth graders :/
Yeah I agree. I was tempted to make an asshole post but then I realized that being sarcastic to an 8th grader is kind of mean.
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On October 14 2009 09:34 Monstah-_- wrote:
...because everything I do to one side I must do to the other, right?
so now my problem is... I subtracted 2p from the right side and added to the left
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On October 14 2009 10:31 micronesia wrote:
As some have pointed out, algebra is not fifth or sixth grade material in the USA. It is usually done in 8th or 9th grade. I did it in math 8 enriched but this was a while ago when math was a little different.
For sure... American high schools aren't the best in the world, on average. They're actually pretty crappy when compared to foreign schools. But American Universities are really really good.
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On October 14 2009 09:54 NSANE.hydra wrote:
For fractions (like 1/2x), you just multiply both sides by the inverse of whatever fraction of x you have.
For example 1/5x = 4
(5/1)1/5x = 4(5/1)
5 times 1/5 is 1, so you're left with x = 20
This is probably confusing you, I'll just let your teacher do it :/
Keep in mind if you're going to ask for help with equations that contain fractions, you need to write it differently. I understood what you were trying to say, but others may not.
1/5x = 4
This reads:
1 divided by 5x equals 4. This would mean that x = .05
Your equation should have been set up in any of these ways:
x(1/5) = 4
(1/5)(x) = 4
Or, as you become more familiar with algebraic equations containing variables, you will come to know that multiplication is distributive, so you could have simply wrote it as x/5, because 1*(x) = x.
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United States24784 Posts
On October 14 2009 13:14 Faronel wrote:Show nested quote +On October 14 2009 10:31 micronesia wrote:
As some have pointed out, algebra is not fifth or sixth grade material in the USA. It is usually done in 8th or 9th grade. I did it in math 8 enriched but this was a while ago when math was a little different. For sure... American high schools aren't the best in the world, on average. They're actually pretty crappy when compared to foreign schools. But American Universities are really really good.
This has nothing to do with the caliber of US high schools in the global competition.
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On October 14 2009 19:47 micronesia wrote:Show nested quote +On October 14 2009 13:14 Faronel wrote:On October 14 2009 10:31 micronesia wrote:
As some have pointed out, algebra is not fifth or sixth grade material in the USA. It is usually done in 8th or 9th grade. I did it in math 8 enriched but this was a while ago when math was a little different. For sure... American high schools aren't the best in the world, on average. They're actually pretty crappy when compared to foreign schools. But American Universities are really really good. This has nothing to do with the caliber of US high schools in the global competition.
Just a little side note... Something that's been bothering me recently. Did you listen to Obama talk about the american school system? He said something like "Asian countries, such as Singapore blah blah blah, have shorter school days but still do better than American schools blah blah blah". FALSE! In most Asian countries academics dominate any student's life. After the "short" school day kids go off to tuition.
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United States24784 Posts
On October 14 2009 20:44 madnessman wrote:Show nested quote +On October 14 2009 19:47 micronesia wrote:On October 14 2009 13:14 Faronel wrote:On October 14 2009 10:31 micronesia wrote:
As some have pointed out, algebra is not fifth or sixth grade material in the USA. It is usually done in 8th or 9th grade. I did it in math 8 enriched but this was a while ago when math was a little different. For sure... American high schools aren't the best in the world, on average. They're actually pretty crappy when compared to foreign schools. But American Universities are really really good. This has nothing to do with the caliber of US high schools in the global competition. Just a little side note... Something that's been bothering me recently. Did you listen to Obama talk about the american school system? He said something like "Asian countries, such as Singapore blah blah blah, have shorter school days but still do better than American schools blah blah blah". FALSE! In most Asian countries academics dominate any student's life. After the "short" school day kids go off to tuition.
If he meant shorter 'mandated' school days perhaps?
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EPT
