Question

81的7次方减27的9次方再减9的13次方怎么被45整除?

Answer 1

81^7-27^9-9^13

=(3^4)^7-(3^3)^9-(3^2)^13

=3^28-3^27-3^26

=9*3^26-3*3^26-3^26

=5*3^26

=45*3^24

所以能被45整除