y x
(1+ -----)÷ -----------
x-y x²-y²
要写详细过程、!!谢谢
y x
(1+ -----)÷ -----------
x-y x²-y²
要写详细过程、!!谢谢
y x
(1+ -----)÷ ---------
x-y x²-y²
x-y+y x
=----------÷----------
x-y (x+y)(x-y)
x (x+y)(x-y)
=--------×------------
x-y x
上下约分得原式为 x+y
原式=X/(X-y) * { (X-y)*(X+y)} /X
=X+y