Finding the GCF in polynomials
(4x^2y)(8x^3y)
expand (4x^2y) into (2)(2)(x)(x)(y)
expand (8x^3y) into (2)(2)(2)(x)(x)(x)(y)
The numbers that the expanded version have in common are:
(2)(2)(x)(x)(y)
when you multiply these together you end up with 4x^2y which is your greatest common factor