Is x greater than zero?

[BTGmoderatorAT]

Is x greater than zero?

(1) x^4 - 16 = 0
(2) x^3 - 8 = 0

What's the best way to determine which statement is sufficient?

[Jay@ManhattanReview]

Is x greater than zero?

(1) x^4 - 16 = 0
(2) x^3 - 8 = 0

What's the best way to determine which statement is sufficient?

(1) x^4 - 16 = 0

=> x = ±4.

If x = 4 > 0, the answer is Yes, however, if x = -4 < 0, the answer is no.

(2) x^3 - 8 = 0

=> x = 2 > 0. The answer is Yes. Sufficient.

The correct answer: B

Hope this helps!

-Jay

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide
_________________
Manhattan Review GMAT Prep

Locations: New York | New Delhi | Seoul | Cairo | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.