Find the zeros of the polynomial function f (x) = x^3-2x^2-8x

Question

Victoria Hardy

Mathematics

9 June, 18:04

Find the zeros of the polynomial function f (x) = x^3-2x^2-8x

+5

Answers (2)

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Luciano Padilla · Answer 1

First factor out that x

f (x) = x (x^2-2x-8)

what 2 numbers multiply to get - 8 and add to get - 2?

-4 and 2

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

set to zero

x-0=0

x=0

x-4=0

x=4

x+2=0

x=-2

the zeroes are at x=-2,0 and 4

Adriana Curry · Answer 2

The roots are x=0,4,-2