(x+y)的平方+(x+2y)(x-2y)等于,要化简的过程要有化简和过程

问题描述:

(x+y)的平方+(x+2y)(x-2y)等于,要化简的过程
要有化简和过程

(x+y)的平方+(x+2y)(x-2y)
=(x+y)^2+(x+2y)(x-2y)
=x^2+2xy+y^2+x^2-4y^2
=2x^2+2xy-3y^2