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Second-Degree Equations

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Source: — Problem Solving |
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by aloneontheedge » Sun Jul 18, 2010 9:38 am
jtwhite14 wrote:If (1/x) - (1/x+1) = (1/x+4), then x could be?

A. 0
B. -1
C. -2
D. -3
E. -4

OA C
Its straight forward.

after cross multiplying x+4 = x^2 + x
x = + or - 2
choose C
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by sk818020 » Sun Jul 18, 2010 9:53 am
Another easy way to eliminate a bunch of the answers would be to think logically about the problem.

You cannot make any of the divisors in the equation zero because then the equation become undefined. So x cannot be 0, -1, or -4. So the answer cannot be A, B, or D. Then you can simply plug in the other two to get the correct answer.

Hope this helps.

Thanks,

Jared
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