When multiplying powers with the same base you write the result as a base raised to the power that is the sum of previous two powers:
[tex]a^m\cdot a^n=a^{m+n}.[/tex]
For example,
[tex]2^5\cdot 2^7=2^{5+7}=2^{12};[/tex]
[tex]3^5\cdot 3^4=3^{5+4}=3^9.[/tex]
