I need help with this proof? I don’t understand them

Without graphing the linear functions, find the coordinates of the point of intersection of their graphs: y=3x−11 and y=4

At the newest animated movie, for every 9 children, there are 4 adults. there are a total of 39 children and adults at the movie.

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).