Question

Find all real zeros of the function.
f(x)=4(x^2-1)(x-3)(x+3)^2

Answer 1

4(x^2 - 1)(x - 3)(x + 3)^2 = 0
(x + 1)(x - 1)(x - 3)(x + 3) = 0
x = -1, 1, 3, -3