计算 {2(x-y)的平方-8(x-y)的平方(x+y)+6y(x-y)的平方}÷2(x-y)的平方 等于
问题描述:
计算 {2(x-y)的平方-8(x-y)的平方(x+y)+6y(x-y)的平方}÷2(x-y)的平方 等于
答
【2(x-y)²-8(x-y)²(x+y)+6y(x-y)²】÷2(x-y)²
=2(x-y)²÷2(x-y)²-8(x-y)²(x+y)÷2(x-y)²+6y(x-y)²÷2(x-y)²
=1-4(x+y)+3y
=1-4x-4y+3y
=1-4x-y