X(5x2 - x)
Maaad confused

Three times the sum of a number and seven is negative thirty-six. what is the number?

Melanie is buying a bathing suit that costs 39.99. she is given a discount at the cash register of $6.00 when she scratched 15% off on a game piece for a store promotion. what will the sale price of melanie’s bathing suit be?

I’m really confused and need your assist me with this question i’ve never been taught