Question

If g(x)<0 for all x and if f(x)= (x² - 4) g(x), then find for what x is f(x)>0

Answer 1

g(x) is negative so for f(x) to be positive we need (x^2-4)>0
(x-2)(x+2) > 0
x>2 or x<2

Answer 2

so x in (-infinitey,-2)U(2,infinity)