(4) Write without exponents.

To write without exponents, you need to expand it. This means multiplying by itself four times:
.

Now, you can simplify it by multiplying the coefficients and the variables:
and .
So, .

However, if you want it completely without exponents, you just form:
(which is 6561), and (which you can’t avoid using raised to the 4th power). Therefore, the final answer is:
or simply .