If x/y > 0, whcih of the following must be true?
- A) xy > 0
- B) (x - y) > 0
- C) (x + y) > 0
- D) None of these
Show answer
Answer: A) xy > 0
Explanation
A) xy > 0. A positive quotient means x and y have the same sign. Two numbers with the same sign always multiply to a positive number, so xy > 0 must hold. The others can fail: x = 1, y = 2 makes x − y negative, and x = y = −1 makes x + y negative.
Asked in: BGDCL 2017
Topic: Algebra