Question

answer should be in simplest form

Answer 1

5a^4+2d is your answer. hope that help

Answer 2

You would first subtract 3a^4 from 8a^4
8a^4-3a^4=5a^4, since you can subtract numbers that are like terms.
Same with 5d and 3d
5d-3d=2d
Then you would put the answers together.
5a^4+2d
So the answer is 5a^4+2d