# simple question but i need help

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• Sep 15th 2006, 04:07 AM
topsquark
Quote:

Originally Posted by chancey
You've done something wrong. Not sure what it is, but this is how I did it

(x-1)/(x+4) = (x+3)/(x-7)

(x-1)/(x+4) - (x+3)/(x-7) = 0

((x-1)(x-7) - (x+4)(x+3)) / ((x+4)(x-7)) = 0

(x-1)/(x-7) - (x+4)/(x+3) = 0

x^2 - 8x + 7 - (x^2 + 7x + 12) = 0

-15x - 5 = 0

-15x = 5

x = -5/15 = -1/3

Line 5 is written incorrectly, but as line 6 is correct I suspect it's just a typo. Both your and Soroban's derivations are correct, you simply used a slightly different method.

-Dan
• Sep 15th 2006, 04:13 AM
chancey
Quote:

Originally Posted by topsquark
Line 5 is written incorrectly, but as line 6 is correct I suspect it's just a typo. Both your and Soroban's derivations are correct, you simply used a slightly different method.

-Dan

Oops, typo. Theres not supposed to be '/' in there
• Sep 15th 2006, 09:36 AM
rpatel
thank you everyone
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