数学题化简求值，见图，各位帮帮忙，感激不尽！！

Question

如题所述

Answer 1

((y*(x^2-4y^2))/(x+2y)^2)*((x^2-2xy+4xy)/(x-2y))
=(y*(x+2y)(x-2y)/(x+2y)^2)*(x(x+2y)/(x-2y))
=(y*(x-2y)/(x+2y))*(x*(x+2y)/(x-2y))
=xy追问

谢谢！！

Answer 2

答案是1
解：原式=y（x-2y）/x+2y*4xy/x-2y+xy（x-2y）/x+2y
=4xy²/x+2y+（x²y-2xy²）/x+2y
=x²y+2xy²/x+2y
=xy（x+2y）/x+2y
=xy
∵x=根号下2-1，y=根号下2+1
∴原式=1

Answer 3

追问

虽然我已经写完了，不过还是谢谢你。