Question

PLEASE HELP IVE BEEN STUCK ON THIS QUESTION FOR 20 MINS IDK :(

Answer 1

Remember
$\frac{x^m}{x^n}=x^{m-n}$
and
if $a^b=a^c$ where a=a, then b=c
so
$\frac{7^9}{7^n}=7^{9-n}=7^3$
$7^{9-n}=7^3$
so
9-n=3
-n=-6
n=6

answer is 6