Only problem 6a. can someone demonstrate how to do this so i can do the rest solo?

as far as I can tell, is simply asking to write two more expressions, that are equivalent to the provided one, namely, grab the provided one and expand it, if you simplify the expanded version, you'd end up with the provided, for example

so let's do 6a1, 6a3 and 6a5.

the answer for this question is 38