How do you factor 8x^3-12x^2+2x-3?

1 Answer
Sep 27, 2016

(8x^3-12x+2x-3=color(green)((2x-3)(4x^2+1))

Explanation:

Notice that the ratio of the coefficients of the terms 8x^3 and 2x: 8:2=4:1
is the same as the ratio of the coefficients of the terms -12x^2 and -3: -12:-3 =4:1

This hints hat we should group the original expression as
color(white)("XXX")(color(red)(8x^3+2x))-(color(blue)(12x^2+3))

color(white)("XXX")=color(red)(2x(4x^2+1)))-color(blue)(3(4x^2+1))

then extracting the common factor (4x^2+1)
color(white)("XXX")=(2x-3)(4x^2+1)

(Note that since 4x^2 >= 0 for AAx in RR,
color(white)("XXX")4x^2+1 can not be equal to 0
color(white)("XXX")and (4x^2+1) has no Real factors.