My little sister wanted me to explain this to her but I forgot... someone please help me 30% of x = 12

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?

Consider the function f(x)=-5x+3 what is f(-2)

Two friends are reading books. jimmy reads a book with 21,356 words. his friend bob reads a book with one-and-a-half times as many words. which expression represents the number of words bob reads?