初一化简求值已知x=2,y=3,求(x+y)(x-y)-(x-y)^2+2y^2的值(x+y)(x-y)-(x-y)^2+2y^2_其他解答

初一化简求值
已知x=2,y=3,求(x+y)(x-y)-(x-y)^2+2y^2的值
(x+y)(x-y)-(x-y)^2+2y^2

人气：284 ℃　时间：2020-05-16 15:49:38

解答

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