Question

Given f(x) = 10/x^2- 7x-30

which of the following is true?

(see attached image, it’s not A)

Answer 1

Answer: f(x) is positive for all x<10

Proof of validity is shown below.

Answer 2

It would be f(x) would be positive for all x>10. That is because when you factor the bottom part you get (x-10)(x+3). 10 would give you 0 at the bottom and that means the answer will be undefined. That means any number above 10 would make it positive.