求[(x²+y²)-(x-y)²+2y(x-y)]÷4y的值,其中2x-y=8.

[(x²+y²)-(x-y)²+2y(x-y)]÷4y的值,其中2x-y=8。=[x²+y²-x²+2xy-y²+2xy-2y²]÷4y=[4xy-2y²]÷4y=2y[2x-y]÷4y=[2x-y]÷2=8÷2=4