Question

Find the zeros of the function.

f(x)= 3x^3- 12x^2- 15x
a. 0, 1, and -5
b. -1 and 5
c. 0, -1, and 5
d. 1 and -5

Answer 1

f(x) = 3x³ - 12x² - 15x

1) Factor Outside: 3x( x² - 4x - 5)

Factor Inside: 3x(x + 1)(x - 5)

2) Set Equal To 0:
3x = 0
x + 1 = 0
x - 5 = 0

3) Solve:
x = 0, -1, 5