BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

exponents problem from off guide 12

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 63
Joined: Tue Mar 31, 2009 3:53 pm

exponents problem from off guide 12

by bfman » Mon Sep 28, 2009 8:32 pm
Official Guide 12th edition. Page 175. Q 164.

If m^-1 = -1/3, then m^-2 is equal to:

I got -1/9 because we do not know whether the - sign is from the numerator or the denominator, and the m^-2 would square the denominator, however the book says 1/9. So I am confused. Are they just assuming that the negative sign is from the denominator?

Thank you!
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 107
Joined: Tue Sep 15, 2009 7:18 pm
Location: Pune, India
Thanked: 6 times
GMAT Score:630

by vivekjaiswal » Mon Sep 28, 2009 9:23 pm
Hi bfman,

I wouldn't have worried about the sign of numerator or the denominator, because when you square the fraction you will square both the numerator and the denominator. So whichever is -ve, on squaring the term you will get a +ve result. Thus
m^-2 = (m^-1)^2 = (-1/3)^2 = 1/9

Hope this helps,
Vivek.
Top
Post new topic Post Reply
• Page 1 of 1