Question

计算x2?y2x2?6x+9÷x+y2x?6的结果是（　　）A．x?yx?3B．2x?3C．2x?2yx?3D．2x?yx?

计算x2?y2x2?6x+9÷x+y2x?6的结果是（　　）A．x?yx?3B．2x?3C．2x?2yx?3D．2x?yx?3

Answer 1

原式=

x2?y2

x2?6x+9

?

2x?6

x+y

＝滚笑

(x+y)(x?y)

(x?3)2

?

2(x?3)

x+y

＝

2(x?y)

x?3

=

2x?2y

x?3

；
故大凯含孙陪选C．