Question

Use the Remainder Theorem to evaluate f(10) for:
f(x) = 2x^3 – 14x^2 - 56x - 40

Answer 1

Explanation:

Since we are told that 10 is a zero,

(x−10) must be a factor:

F(x)=2x3−14x2−56x−40

F(x)=(x−10) (2x2+6x+4)

F(x)=2(x−10)(x2+3x+2)

F(x)=2(x−10)(x+2)(x+1)

So the other two zeros are

x = -2 and x= −1