(1).（x+y)² -(x+y)三次方(2).(x-y)² -(x-y)三次方(3).(x-y)² -(y-x)三次方(4).2(x-y) -3(y-x)²

(1).（x+y)² -(x+y)三次方(2).(x-y)² -(x-y)三次方(3).(x-y)² -(y-x)三次方(4).2(x-y) -3(y-x)²
(1).（x+y)² -(x+y)三次方
(2).(x-y)² -(x-y)三次方
(3).(x-y)² -(y-x)三次方
(4).2(x-y) -3(y-x)²

(1).（x+y)² -(x+y)三次方(2).(x-y)² -(x-y)三次方(3).(x-y)² -(y-x)三次方(4).2(x-y) -3(y-x)²
(1).（x+y)² -(x+y)三次方=(x+y)²[1-(x+y)]=(x+y)²(1-x-y)
(2).(x-y)² -(x-y)三次方=(x-y)²[1-(x-y)]=(x-y)²(1-x+y)
(3).(x-y)² -(y-x)三次方=(x-y)²+(x-y)三次方=(x-y)²[1+(x-y)]=(x-y)²(1+x-y)
(4).2(x-y) -3(y-x)²=2(x-y)-3(x-y)²=(x-y)[2-3(x-y)]=(x-y)(2-3x+3y)

(1).（x+y)² -(x+y)三次方
=(x+y)²（1-x-y）
(2).(x-y)² -(x-y)三次方
=(x-y)²（1-x+y）
(3).(x-y)² -(y-x)三次方
=(x-y)² +(x-y)³
=(x-y)²（1+x-y）
(4).2(x-y) -3(y-x)²
=2(x-y) -3(x-y)²
=(x-y)(2-3x+3y)

(1)(x+y)² -(x+y)³
=(x+y)²(1-x-y)
(2)(x-y)² -(x-y)³
=(x-y)²(1-x+y)
(3)(x-y)² -(y-x)³
=(x-y)² +(x-y)³
=(x-y)²(1+x-y)
(4)2(x-y) -3(y-x)²
=2(x-y) -3(x-y)²
=(x-y)(2-3x+3y)

1、(x+y)^2 ×(1 -x+y)
把三次方写成（x＋y）^2 ×（x＋y ）后提取（x＋y）^2