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27 Dec 2021, 08:05
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I picked 2 for X and i came out at choice B.
If X=2
f(x)=x-1/x, since we picked smart-number 2 for X f(2)= 2-1/2= 1,5
The question asks which of the following equals f(1/x), since we picked smart number 2 for X, then the questions becomes which of the following equals f(1/2)?
First we need to solve f(1/2)= 1/2 -1/1/2 = 1/2-2= -1,5 (Info:1/1/2=2)
The question now is which of the following choices gives us -1,5 or -3/2 if we plugg in 2 for X.
Choice B does exact that, and here is how.
B= f(-x), since we picked smart number 2 for X, choice B becomes f(-2)
f(-2)= -2-1/-2 (dubble negative becomes positive +), thus it becomes -2 + 1/2= -1,5 or -3/2.
choice B!
If X=2
f(x)=x-1/x, since we picked smart-number 2 for X f(2)= 2-1/2= 1,5
The question asks which of the following equals f(1/x), since we picked smart number 2 for X, then the questions becomes which of the following equals f(1/2)?
First we need to solve f(1/2)= 1/2 -1/1/2 = 1/2-2= -1,5 (Info:1/1/2=2)
The question now is which of the following choices gives us -1,5 or -3/2 if we plugg in 2 for X.
Choice B does exact that, and here is how.
B= f(-x), since we picked smart number 2 for X, choice B becomes f(-2)
f(-2)= -2-1/-2 (dubble negative becomes positive +), thus it becomes -2 + 1/2= -1,5 or -3/2.
choice B!
JDLaw
Joined: 07 Jul 2021
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Concentration: Marketing, Strategy
Schools: McDonough '26 (WL) Rice Jones '26 (WL) Kenan-Flagler '26 (D) Ross '26 (D) McCombs '26 (D) Owen '26 (A$$$) Kelley '26 (A$$) Goizueta '26 (D) Simon '26 (D) Foster (A$$) ESADE'26 (WL) IE Sep'24 intake (A) Tuck '26 (D)
GMAT 1: 640 Q44 V33
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GMAT 3: 720 Q49 V39
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08 Oct 2022, 04:46
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felippemed
In my experience solving such function problems when options ask to equate to similar function are best done by plugging numbers, works great on higher level problems as well.
plug x=2,
From Stem, f(2)=3/2
f(1/2)=1/2-1/(1/2)=1/2-2=-3/2
which is equal to - f(2) and thinking on the same lines is equal to f(-2) (You can plug -2 and try)
Therefore Ans-B
22 Dec 2025, 17:12
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