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Simplification

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Simplification

by vinviper1 » Thu May 29, 2008 10:16 am
If x does not equal 2

then 3x^2(x-2)-x+2 / x-2

A 3x^2 - x + 2
B 3x^2 + 1
C 3x^2
D 3x^2 - 1
D 3x^2 - 2


I cheated and plugged in one to get the ans (D). The OG had an odd way to get it. Any better ways out there? Thanks
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by aatech » Thu May 29, 2008 10:41 am
Can you please put the brackets properly to distinguish the statements...
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by gmatinjuly » Thu May 29, 2008 11:14 am
hey vinviper though ur approach is fine as long as it gets u an answer I think this would be easier ....

3 x^2 (x-2) - x + 2 /x-2

Now lets solve numerator first

3x^2 (x-2)-x+2
= 3x^2 (x-2) -1 (x-2)
= (x-2) (3 x^2 - 1)

No we can cancel (x-2)

so that leaves 3 x ^2 - 1 that is D
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by jasonc » Thu May 29, 2008 11:19 am
plugging in 1 or 0 is the easist (arguably the fastest) way to solve this problem. Since the answer choices will obviously be different (they'll all be off by 1, cept the first choice, so just make sure you don't plug in a number that will make x+2 = -2,-1,0,1).

You can also do it through algebra.
[3x^2(x-2)-x+2]/(x-2)
=[3x^2(x-2)]/(x-2)+(-x+2)/(x-2)
=3x^2+(-x+2)/(x-2)
=3x^2-(x-2)/(x-2)
=3x^2-1
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