Answer:
(5.4)^9
Explanation:
You want the simplified form of (5.4)(5.4^2)^4.
Integer exponents
It can be useful to think of integer exponents as telling you how many times the base is a factor in the product.
(5.4)(5.4^2)^4 = (5.4)·((5.4)(5.4))^4
= (5.4)·((5.4)(5.4))·((5.4)(5.4))·((5.4)(5.4))·((5.4)(5.4))
Eliminating excess parentheses, we see the product is ...
= (5.4)(5.4)(5.4)(5.4)(5.4)(5.4)(5.4)(5.4)(5.4)
This has 9 factors of 5.4, so ...
= (5.4)^9