2(x-y)^2-x+y
=2(x-y)(x-y)-(x-y)
=(x-y)(2x-2y-1) .提取公因式
提取出x-y后
第一项剩2(x-y),第二项剩-1
其实就是乘法分配律
=2(x-y)(x-y)-(x-y)
=(x-y)(2(x-y)-1)
=(x-y)(2x-2y-1)
2(x-y)^2-x+y
=2(x-y)(x-y)-(x-y)
=(x-y)(2x-2y-1) .提取公因式
提取出x-y后
第一项剩2(x-y),第二项剩-1
其实就是乘法分配律
=2(x-y)(x-y)-(x-y)
=(x-y)(2(x-y)-1)
=(x-y)(2x-2y-1)