Answer:
The exponents of a start at n and decrease until they reach 0 . The exponents of b start at 0 and increase until they reach n
Step-by-step explanation:
The general formula for
is:

Therefore, the exponents of a start at n and decrease until they reach 0 . The exponents of b start at 0 and increase until they reach n
(7+3)x(4-2)=39
I hope that helps
Add the pic and I’ll be able to answer it