先化简,再求值:2x²-2y²分之4x²-8xy+4y²乘xy(x-y)分之(x+y)²,其中x=2,y=3...

先化简,再求值:2x²-2y²分之4x²-8xy+4y²乘xy(x-y)分之(x+y)²,其中x=2,y=3...
先化简,再求值:2x²-2y²分之4x²-8xy+4y²乘xy(x-y)分之(x+y)²,其中x=2,y=3...

先化简,再求值:2x²-2y²分之4x²-8xy+4y²乘xy(x-y)分之(x+y)²,其中x=2,y=3...
原式=4(x-y)²/2(x+y)(x-y)*(x+y)/xy(x-y)
=2(x-y)/(x+y)*(x+y)/xy(x-y)
=2/xy
=2/(2*3)
=1/3