Carcass wrote:
If \(|ab| > ab\), which of the following must be true?
I. \(a < 0\)
II. \(b < 0\)
III. \(ab < 0\)
A. I only
B. II only
C. III only
D. I and III
E. II and III
We can quickly eliminate 4 of the 5 answer choices by
testing values that satisfy the given inequality, \(|ab| > ab\)
For example, we can see that \(a = 1\) and \(b = -1\) satisfies the given inequality.
When we scan statements I, II and III, we see that statement I is not necessarily true.
This means we can eliminate answer choices A and D, since they state that statement I must be true.
Another pair of values that satisfied to give an inequality is \(a = -1\) and \(b = 1\)
When we scan the statements, we see that statement II is not necessarily true, which means we can eliminate answer choices B and E, since they state that statement II must be true.
By the process of elimination, the correct answer must be C