How do you factor completely −12x^3y^5 − 9x^2y^2 + 12xy^312x3y59x2y2+12xy3?

1 Answer
Apr 13, 2017

-12x^3y^5-9x^2y^2+12xy^3 = -3xy^2(4x^2y^3+3x-4y)12x3y59x2y2+12xy3=3xy2(4x2y3+3x4y)

But note that:

color(red)(9x^4y^4)-12x^3y^5-9x^2y^2+12xy^3 = 3xy^2(xy-1)(xy+1)(3x-4y)9x4y412x3y59x2y2+12xy3=3xy2(xy1)(xy+1)(3x4y)

Explanation:

Given:

-12x^3y^5-9x^2y^2+12xy^312x3y59x2y2+12xy3

First note that all of the terms are divisible by 33, xx and y^2y2, and hence by 3xy^23xy2. So we can separate that out as a factor. I will use -3xy^23xy2 because I prefer positive leading coefficients:

-12x^3y^5-9x^2y^2+12xy^3 = -3xy^2(4x^2y^3+3x-4y)12x3y59x2y2+12xy3=3xy2(4x2y3+3x4y)

It is not possible to factor this further.

I suspect that a leading term 9x^4y^49x4y4 is missing from the question, since we find:

9x^4y^4-12x^3y^5-9x^2y^2+12xy^3 = 3xy^2(3x^3y^2-4x^2y^3-3x+4y)9x4y412x3y59x2y2+12xy3=3xy2(3x3y24x2y33x+4y)

color(white)(9x^4y^4-12x^3y^5-9x^2y^2+12xy^3) = 3xy^2((3x^3y^2-4x^2y^3)-(3x-4y))9x4y412x3y59x2y2+12xy3=3xy2((3x3y24x2y3)(3x4y))

color(white)(9x^4y^4-12x^3y^5-9x^2y^2+12xy^3) = 3xy^2(x^2y^2(3x-4y)-1(3x-4y))9x4y412x3y59x2y2+12xy3=3xy2(x2y2(3x4y)1(3x4y))

color(white)(9x^4y^4-12x^3y^5-9x^2y^2+12xy^3) = 3xy^2(x^2y^2-1)(3x-4y)9x4y412x3y59x2y2+12xy3=3xy2(x2y21)(3x4y)

color(white)(9x^4y^4-12x^3y^5-9x^2y^2+12xy^3) = 3xy^2((xy)^2-1^2)(3x-4y)9x4y412x3y59x2y2+12xy3=3xy2((xy)212)(3x4y)

color(white)(9x^4y^4-12x^3y^5-9x^2y^2+12xy^3) = 3xy^2(xy-1)(xy+1)(3x-4y)9x4y412x3y59x2y2+12xy3=3xy2(xy1)(xy+1)(3x4y)