Question

初一数学，急~~~~先化简再求值2(x-y)平方-(y-x)平方-(x+y)(y-x)其中x=3，y=-2

过程越详细越好，谢谢

Answer 1

全部展开，y全部消去，最后变成2x∧2

(⊙o⊙)哦不是这样的

等下，发张图

Answer 2

原式=2(x-y)²-(x-y)²+(x+y)(x-y)
=(x-y)²+(x+y)(x-y)
=(x-y)(x-y+x+y)
=2x(x-y)
=2*3*(3-(-2))
=30