Can someone please answer 19,20,21 please and thank you!!

The answer for 19 is a & d
The answer for 20 is 8607
The answer for 21 is 85.10
Even though I am a senior in high school I know the answer

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?