Help needed here!

What is the expression for f(x), when we rewrite $3^{5x+3} \cdot 27^{x}$, as $3^{f(x)}$ ?

https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:exp/x2ec2f6f830c9fb89:equivalent-exp/e/rewrite-exponential-expressions

I need help with this problem, and I watched the video before it but it was confusing for me. Could somebody explain the question or help me solve it?

Thank you,

$tommarvoloriddle$

EDIT:

Ok, I forgot to include what I tried and what I am stuck on:

$3^{3^{5x+3} \cdot 27^{x}}$

Then I simplified a bit:

$3^{3^{8x+3}}$

and now, I have no idea what to do.

It would be great if you could help from there!