Question

What are the zeros of f (x) = 2x^3– 8x?

O {4, -2}
O {0, 2}
O{-2, 0, 2}
O {2, -2}

Answer 1

{ - 2, 0, 2 }

Explanation:

To find the zeros let f(x) = 0 , that is

2x³ - 8x = 0 ← factor out 2x from each term

= 2x(x² - 4) = 0 ← (x² - 4) is a difference of squares

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

Equate each factor to zero and solve for x

2x = 0 ⇒ x = 0

x - 2 = 0 ⇒ x = 2

x + 2 = 0 ⇒ x = - 2

solution is { - 2, 0, 2 }