if a function f is defined by f(x)

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if a function f is defined by f(x) [#permalink]

16 Dec 2010, 18:37

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Q. if a function f is defined by f(x)= -1/x for all non zero numbers x. If f(a) = -1/2 and f(ab) = 1/6 then b= ?

a. 3
b. 1/3
c. -1/3
d. -3
e. -12

I have a doubt about the correct ans
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Ajit

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Re: if a function f is defined by f(x) [#permalink]

16 Dec 2010, 19:14

I say D. what is the OA..

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Re: if a function f is defined by f(x) [#permalink]

16 Dec 2010, 19:34

f(a) = -1/a = -1/2 => a=2
f(ab) = -1/ab = 1/6 => ab = -6 => b = -6/a = -6/2 = -3

Hence, D.

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Re: if a function f is defined by f(x) [#permalink]

17 Dec 2010, 09:12

yup thts the correct ans...thanks guys for confirming the ans
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Re: if a function f is defined by f(x) [#permalink] 17 Dec 2010, 09:12

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if a function f is defined by f(x)

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