Draw a triangle and a line that has a slope of -1 1/2 HELP ASAP!!

The answers are 20,30,80,180,960,890,1230,4560. on the first row

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?