Question

一道数学题，急求

((x-y)/(x+2y))/((x^2-y^2)/(x^2-4xy+4y^2))-2当x=2+√3, y=2-√3时，化简求值上面的式子

Answer 1

((x-y)/(x+2y))/((x^2-y^2)/(x^2-4xy+4y^2))-2
=((x-y)/(x+2y))/((x-y)(x+y)/(x-2y)(x-2y)-2
=(x+2y)(x-2y)(x-2y)/(x+y)-2
=(x^2-y^2)(x-2y)/4-2
=8(3^(1/2))(6-3^(1/2))/4-2
=12(3^(1/2))-8

Answer 2

（2+√3-2+√3）/（2+√3+4-2√3)=2√3/6-√3
本人就能算出那么多啦！！！剩下的不会啦！

Answer 3

((x-y)/(x+2y))/((x^2-y^2)/(x^2-4xy+4y^2))-2
=((x-y)*(x+2y)*(x-2y))/((x+2y)*(x+y)*(x-y))-2
=(x-2y)/(x+y)-2
=(2+√3-2(2-√3))/(2+√3+2-√3)-2
=(3√3-2)/4-2
=(3√3-10)/4

Answer 4

-17-4√3/(6-√3)/4