|
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?
  
|
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.
|
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.
|
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!
|
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.
|
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.
|
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.
|
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..
|
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
|
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.
|
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..
|
This is 5th grade work. I hope OP is trolling, otherwise this is really sad =[
|
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 :/
|
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.
|
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
|
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
|
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
|
Osaka27149 Posts
Keep it all in one thread please. You may also want to brush up on your beginner spelling. :p
|
I learned algebra in 8th grade as well
?_?
|
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.
|
|
|
|
|
|
EPT
