Answer:
14) 2p^2+3p+4
16) 5w^3+5w^2+5w+5
18) 3k^3-6k^2+4k-3
20) -4a^2-3ab
I hop this is right! I learned this in like 9th grade and im about to be a freshman in college!!!
Explanation:
you combine like terms while still following the negative and positive in front of them. If there is no like term then you just bring it straight down but the order is by highest exponent.