What does it mean to evaluate a function?

If u good at math hit me up on insta or sum @basic_jaiden or @ and

The function f(x)= x5+ ( x + 3)2 is used to create a table. if x = -1 then what is f(x)?

Neal buys a board game. he pays for the board game and pays $1.54 in sales tax. the sales tax rate is 5.5%. what is the original price of the board game, before tax