Need Math Help, Please!
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12-02-2013, 07:26 PM
Need Math Help, Please!
Okay, I've heard people say they are willing to help with math, so I am here to take you up on your offer. I'm working on polynomials, something I've did before, but I'm a bit rusty. So I was doing okay, until I got to this problem, and I cannot understand why it is being marked as wrong. The computer tells me "Although your answer is equal to the correct answer it is in the wrong form." though it doesn't provide any instruction as to what form it wants. In any case, after getting it wrong three times it was marked as wrong and it provided me with the correct response. Only thing is, I do not even understand how the correct answer is equal my to answer. Here is the problem:

(11r^2s+15rs-4-5r^2s^2)-(3sr^2+7-7r^2s^2)

I took the reciprocal of the terms, did my calculations and wound up with
11r^2s+15rs-11+2r^2s^2-3sr^2
The answer it wanted was
8r^2s+15rs-11+2r^2s^2

From observation it would seem that it wanted me to subtract -3sr^2 from 11r^2s, but those aren't like terms are they? since when does sr^2 = r^2s? Can someone please clarify? If this is indeed the case can someone please explain how or why these are like terms so I can recognize it in future problems? Thanks in advance!

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12-02-2013, 07:40 PM
RE: Need Math Help, Please!
r and s are variables here right? I don't want to get it all wrong from the start and the notation is weird Tongue

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12-02-2013, 07:45 PM
RE: Need Math Help, Please!
Shocking Thud...

medic...

See here they are, the bruises, some were self-inflicted and some showed up along the way. - JF
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12-02-2013, 07:51 PM (This post was last modified: 12-02-2013 08:02 PM by Dark Light.)
RE: Need Math Help, Please!
Unfortunately the forum doesn't allow for alt codes so my only other course of action would be to upload a word file or type it in a word doc, take a screenshot, upload it to a site that hosts images and link to it. This seemed like the easiest course of action but ^2 = squared, and yes the the letters are variables.

edit: If this helps here is a pic of my work, ignore the bit on the bottom left corner, that is a different problem.

[Image: ?ui=2&ik=c8649afbcf&view...amp;amp;zw]

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12-02-2013, 08:01 PM
RE: Need Math Help, Please!
Yeah, my problem was with the letters (I'm used to x and y)
Ok, the problem is that sr^2 is equal to r^2s because multiplication is commutative and those two variables are in a multiplication. So in the same way that xy=yx then r^2s=sr^2 (the square only applies only to the r because they're not in brackets) Big Grin

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12-02-2013, 08:11 PM
RE: Need Math Help, Please!
(12-02-2013 08:01 PM)nach_in Wrote:  Yeah, my problem was with the letters (I'm used to x and y)
Ok, the problem is that sr^2 is equal to r^2s because multiplication is commutative and those two variables are in a multiplication. So in the same way that xy=yx then r^2s=sr^2 (the square only applies only to the r because they're not in brackets) Big Grin
So, I understand that xy=yx, but wouldn't r^2s be r times r times s, whereas rs^2 be r times s times s? I still don't get it.

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12-02-2013, 08:17 PM
RE: Need Math Help, Please!
yeah, but you wrote r^2s and sr^2, not rs^2

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12-02-2013, 08:57 PM
RE: Need Math Help, Please!
D'oh! I'm a big dummy! Thanks nach in! Much appreciated. I honestly didn't see where I was fucking up until I replaced the variables with numbers, then I saw it and did a facepalm. I suck at math. Thanks again!

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12-02-2013, 10:23 PM
RE: Need Math Help, Please!
any time Big Grin

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12-02-2013, 11:24 PM
RE: Need Math Help, Please!
Damn. The answer I got was:

K9%^O$)(*FND8(&#$JKHDFUY#$)

Is that right?
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