If b 0 and -1

Question

If b ≠ 0 and -1 < \frac{a}{b} < 1 , which of the following CANNOT be true? A. a + b < 0 B. (a + b)(a − b) > 0 C. a − b > 0 D. (a + b)(a − b) < 0 E. a + b > 0 Are You Up For the Challenge: 700 Level Questions

WizakoBaskar · Accepted Answer

-1 < \frac{a}{b} < 1  means   \frac{|a|}{|b|} < 1 
So, |a| < |b|

The easiest way to solve when we have absolute values on both sides of the inequality is to square both sides
 a^2 < b^2 
Or  a^2 - b^2 < 0

i.e., (a + b)(a - b) < 0
If the product of (a + b) and (a - b) is negative, one of (a +b) or (a - b) is positive and the other is negative. So, options A, C, and E are possible.

The only answer option that is not possible is that (a + b)(a - b) > 0.

All the other answer options are possible.
Choice B is the answer

shubhim20 · Answer

why can't this be C  Bunuel   bb   KarishmaB

bb · Answer

Let's do it this way - give a pair of numbers that you think a and b can be, can I can tell you why they can't work. 
Which pair do you think is realistic for a and b that meets the conditions?

If b 0 and -1 < a/b < 1, which of the following CANNOT be true?

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