Question

Zachary purchased a computer for $1900 on a payment plan. four months after he purchased the computer, his balance was $1420. seven months after he purchased the computer his balance was 1060. what is an equation that models the balance b after m months

Answer 1

The equation that models the balance b after m months for Zachary's computer purchase on a payment plan is b = 1900 - 120m, reflecting a $120 monthly decrease in the balance.

Step-by-step explanation:

The student is looking for an equation that models the balance b after m months for a computer purchase on a payment plan. Given the initial purchase price of $1900 and the balances after 4 and 7 months, we need to find the rate at which the balance decreases each month.

We have two points that can help us create this equation, where (m, b) refers to (month, balance): (4, $1420) and (7, $1060). To find the monthly rate of decrease, we subtract the later balance from the earlier balance and divide by the number of months between the two observations.

Monthly decrease = ($1420 - $1060) ÷ (7 - 4) = $360 ÷ 3 = $120 per month

Since the balance is decreasing by $120 per month, we can express this with the equation b = 1900 - 120m, which accurately models the balance after m months.