Question

化简：

x2-y2

x+y

-

4x(x-y)+y2

2x-y

Answer 1

分析：首先把各分式进行约分，然后进行加减运算．

解答：解：原式=

(x+y)(x-y)

x+y

-

4x2-4xy+y2

2x-y

=x-y-

(2x-y)2

2x-y

=x-y-2x+y
=-x．

点评：本题不必要把两式子先通分，约分后就能加减运算了．