One number is 24 minus three times another number. Five times the first number added to three times the other number is 36. Find the numbers.

For the first one, first find your slope (), then use f(x)=mx+b. Your slope would be . Your y-intercept is given as (0,5), so your equation of the line would be f(x)=(-5/2)x+5. For the second one, first you find what is constant. As your 3500 is a one time purchase, it is your constant, which will be your y-intercept. Your slope would be whatever changes over time, which is your maintenance cost of 125. This creates the equation f(x)=mx+b => f(x)=125x+3500.