aashaybaindurgmat wrote:
If \(f(w) =\frac{1}{w} + \frac{1}{w+8}\) and the function f(w) equals \(\frac{1}{w-1}\), then a possible value for w could be
A) -8
B) -4
C) -2
D) -1
E) 3
(Source: Princeton Review GMAT Practice Test 6)
This math just looks time-consuming. It is not. Numbers are easy.*
\(f(w) =\frac{1}{w} + \frac{1}{w+8}\)
And\(f(w) = \frac{1}{w-1}\) . Set them equal.
\(\frac{1}{w-1} = \frac{1}{w} + \frac{1}{w+8}\)
\(\frac{1}{w-1} =
\frac{(w+8)+w}{w(w+8)}\)
\(\frac{1}{(w-1)} =
\frac{2w+8}{w^2+8w}\)
\((2w+8)(w-1) = w^2 + 8w\)
\(2w^2 - 2w + 8w - 8 = w^2 + 8w\)
\( w^2 - 2w - 8 =\)
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