Write an expression to show the sum of x and y

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

Rewrite the following quadratic functions in intercept or factored form. show your work. f(x) = 3x^2 - 12