(x-y)的平方怎么算

Question

如题所述

Answer 1

你好哦~
直接去括号，为：
(x-y)(x-y)
=x^2-xy-xy+y^2
=x^2-2xy+y^2本回答被网友采纳

Answer 2

(x-y)²=x²-2xy+y²

Answer 3

x-y=3
(x-y)²=9
x²+y²-2xy=9
x²+y²-4=9
x²+y²=5

(x²+y²)²=25
x^4+y^4+2x²y²=25
x^4+y^4+8=25
x^4+y^4=17