PLEASE HELP BRO I WILL GIVE YOU BRAINLIEST Given a_{5} = - 12 and a_{12} = 65 are terms of an arithmetic sequence:
a. Write Explicit and Recursive rules for this sequence
b. Assume this sequence extends past the 12th term, find the 18th term.
c. Assuming this sequence has 20 terms, find the sum of the first 20 terms.