Please help with this. This is calculus

James is playing his favorite game at the arcade. after playing the game 3 times, he has 8 tokens remaining. he initially had 20 tokens, and the game costs the same number of tokens each time. the number t of tokens james has is a function of g, the number of games he plays. write the function’s formula? t=

Solve each quadratic equation by factoring and using the zero product property. x^2 + 18x = 9x

Solve for x: 5/3 x = 20/21 it's fraction. remember to simplify your fraction