{(z+y)(x-y)-(x-y)的2次方+2y(x-y)}除以4y

问题描述:

{(z+y)(x-y)-(x-y)的2次方+2y(x-y)}除以4y

(x-y)(z+y-x+y+2y)÷4y
=(x-y)(z-x+4y)÷4y
{( x +y)(x-y)-(x-y)的2次方+2y(x-y)}除以4y
=(x-y)(x+y-x+y+2y)÷4y
=(x-y)(4y)÷4y
=x-y