How to solve for x .Need help ASAP

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.

Ineed with math stuff it involves graphs

Find the greatest common factor of the followig monomials 46g^2h and 34g^6h^6