when multiplying powers, add the exponents.
when dividing powers, subtract the exponent of the "bottom" from the exponent of the "top".
(the exponents are the things you are calling "indices", which isn't the right name for them).
If we do it for you, you'll learn nothing. Try it yourself.
$\displaystyle x^a\times~x^b=x^{a+b}$
It's a simple enough rule to apply.
$\displaystyle 3^2\times~3^5=3^{2+5}=3^7$
If you wish to receive further help, then please present an effort.