问题 选择题
已知:am=7,bn=
1
7
,则(-a3mbn2(amb2n3的值为(  )
A.1B.-1C.7D.
1
7
答案

(-a3mbn2(amb2n3

=(am6(bn2(am3(bn6

=(am9(bn8

=79×(

1
7
8

=78×(

1
7
8×7

=(7×

1
7
8×7

=7.

故选:C.

单项选择题
单项选择题