Question

证明81的七次方-27的九次方-9的13次方被45整除

Answer 1

81^7-27^9-9^13

=3*27^9-27^9-9*27^8

=27^8(3*27-27-9)

=27^8*45

因式中有45,因此81^7-27^9-9^13能被45整除.