-4(x+2y)的平方+25(x-y)的平方

问题描述:

-4(x+2y)的平方+25(x-y)的平方

-4(x+2y)的平方+25(x-y)的平方
=25(x-y)²-4(x+2y)²
=(5x-5y)²-(2x+4y)²
=(5x-5y+2x+4y)(5x-5y-2x-4y)
=(7x-y)(3x-9y)
=3(7x-y)(x-3y)