How do you factor f(x)=2x^3-10x^2-8x+40?

1 Answer
May 14, 2016

(x-2) (2x-10) (x+2)

Explanation:

First, find a factor of f(x)

try f(1)

f(1) = 24 therefore is not a factor

next try f(2)

f(2) = 0 therefore (x-2) is a factor of f(x) = 2x^3 - 10x^2 - 8x - 40

Now, divide f(x) = 2x^3 - 10x^2 - 8x - 40 by (x-2) using long division.

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= (x-2) (2x^2 -6x -20)

Then simplify this so

= (x-2) (2x-10) (x+2)