Question

化简：2（x+2y）^2-7（x+2y）^3+8(2y+x)^2-2(2y+x)^3

Answer 1

原式=-9(x+2y)^3+10(x+2y)^2

=-(x+2y)^2[9(x+2y)-10]

=-(x+2y)^2(9x+18y-10)