Question

Find the zeros of the function. f(x) = 4x3 - 12x2 - 40x

Answer 1

first take out the GCF which is 4x

 4x (x^2 - 3x - 10) = 0

4x(x - 5)(x + 2) = 0

4x = 0  so x = 0

x - 5 = 0 so x = 5

x+2 = 0 so x = -2

zeros are  -2, 0 and 5