Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

If a and b are negative integers, which of the . . . .

Expert replies
by Vincen » Tue Jan 16, 2018 9:21 am
If a and b are negative integers, which of the following statements must be true?

I. (-a)^b is positive.
II. (-a)^(-b) is positive.
III. a^(-b) is positive.

A. None
B. II only
C. I and II only
D. I and III only
E. I, II and III

The OA is the option C.

How can I verify which options are true? Experts, can you help me here? Please.
Join the discussion
Source: — Problem Solving |

by EconomistGMATTutor » Tue Jan 16, 2018 10:14 am
Hello Vincen.

Let's take a look at your question.

If we choose a = -2 and b = -3, we will have

I. (-a)^b = (2)^(-3) = 1/(2^3) --> Positive
II. (-a)^(-b) = 2^3 --> Positive
III. a^(-b) = -2^3 --> Negative

Then, the correct answer is the option C.

I hope this answer can help you to understand.

I'm available if you'd like a follow-up.

Regards.
GMAT Prep From The Economist
We offer 70+ point score improvement money back guarantee.
Our average student improves 98 points.

Image
Join the discussion

by Jeff@TargetTestPrep » Mon Feb 26, 2018 10:43 am
Vincen wrote:If a and b are negative integers, which of the following statements must be true?

I. (-a)^b is positive.
II. (-a)^(-b) is positive.
III. a^(-b) is positive.

A. None
B. II only
C. I and II only
D. I and III only
E. I, II and III
We can say a = -2, and b = -1.

I. (-a)^b = (-(-2))^-1 = 2^-1 = 1/2

Thus, (-a)^b is positive.

II.(-a)^(-b) = (-(-2))^(-(-1)) = 2^1 = 2

Thus, (-a)^(-b) is positive.

III. a^(-b) = -2^-(-1) = -2^1 = -2

Thus, a^(-b) IS NOT positive.

Answer: C

Jeffrey Miller
Head of GMAT Instruction
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
Join the discussion