Can somebody please explain to me how to do this? I don't understand how to do this

This stem-and-leaf plot represents the heights of the students on ralph's basketball team. one student's height is missing from the plot. if the mean height of all the students on the team is 61 inches, what is the missing height? a. 55 in. b. 59 in. c. 61 in. d. 65 in.

What is the inverse of the function f(x) = 2x + 1?

Complete the equation of the live through (-1,6) (7,-2)