Question

初一的一个计算题,快来啊(x-4y)(2x+3y)(x+2y)(x-y)

Answer 1

(x-4y)(2x+3y)(x+2y)(x-y)

=[(x-4y)(2x+3y)][(x+2y)(x-y)]

=(2x^2+3xy-8xy-12y^2)(x^2-xy+2xy-2y^2)

=(2x^2-5xy-12y^2)(x^2+xy-2y^2)

=2x^4+2x^3y-4x^2y^2-10x^3y-5x^2y^2+10xy^3-12x^2y^2-12xy^3+24y^4

=2x^4-8x^3y-21x^2y^2-2xy^3+24y^4

这题有点麻烦.