What is the product of nine and four less than n is 20

Sorry guys but as you have a small brain

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10