3^n-3^(n-1)要怎么化简?

问题描述:

3^n-3^(n-1)要怎么化简?
3^n+3^(n-1)
这个也顺便说一下

3^n-3^(n-1)
=3^n-3^n/3
=(3^n*3-3^n)/3
=(2/3)*3^n
3^n+3^(n-1)
=3^n+3^n/3
=(3^n*3+3^n)/3
=(4/3)*3^n