Im not exactly sure what to do, could someone help me out?

Determine the mean and variance of the random variable with the following probability mass function. f(x)=( 729divided by 91) (1 divided by 9) superscript x baseline comma x equals 1,2,3 round your answers to three decimal places (e. g. 98.765).

For f(x) = 3x+1 and g(x) = x2 - 6, find (g/f)(x)

With both problems. a. s.a. p directions on photo ^