How do you factor 9x^3-36x^2-25x+100?

1 Answer
EZ as pi
Sep 1, 2016

(x-4)(3x+5)(3x-5)

Explanation:

There are 4 terms, but there is no common factor in all the terms,
Pair the terms to make common factors, make sure there is a + sign between the pairs.

9x^3 -36x^2 -25x+100 " = "(9x^3 -36x^2)+ ( -25x+100)

=9x^2(x-4) color(magenta)(+) 25(color(blue)(-x+4))

=9x^2(x-4) color(magenta)(-) 25(color(blue)(x-4)) larr" " note sign change.

=(x-4)(9x^2 -25)

=(x-4)(3x+5)(3x-5)

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