Solution-
Zachary purchased a computer for 1800 on a payment plan. (Initial Money)
3 months after he bought the computer, his balance was 1350. (Money after 3 months)
Total money paid in 3 months = 1800-1350 = 450
Money paid per month = 450/3 = 150
5 months after he bought the computer, his balance was 1050.
Total spent = 1800-1050 = 750 = (5× 150)
So the equation that models the balance b after m months,
b = 1800 - m(150)
∴ Here, the slope signifies the constant monthly deduction of $150.
