化简：x-yx+3y÷x2-y2x2+6xy+9y2-2yx+y

题型：解答题难度：一般来源：莱芜

化简：

x-y

x+3y

÷

x2-y2

x2+6xy+9y2

-

2y

x+y

答案

原式=

x-y

x+3y

•

x2+6xy+9y2

x2-y2

-

2y

x+y

=

x-y

x+3y

•

(x+3y)2

(x+y)(x-y)

-

2y

x+y

=

x+3y

x+y

-

2y

x+y

=

x+y

x+y

=1．