Can you guys please help me im confused

Which is an equation for the nth terms of the sequence 12,15,18,21

30 points and i will give brainliest the club will base its decision about whether to increase the budget for the indoor rock climbing facility on the analysis of its usage. the decision to increase the budget will depend on whether members are using the indoor facility at least two times a week. use the best measure of center for both data sets to determine whether the club should increase the budget. assume there are four weeks in a month. if you think the data is inconclusive, explain why.

At a sale this week, a desk is being sold for $213. this is a 29% discount from the original price. what is the original price?