Question

Dominic borrowed some money from his friend in order to help buy a new video

game system. Dominic agreed to pay the friend back some amount every week until
his loan was paid off. Let L represent the amount Dominic owes his friend after t
weeks. A graph of L is shown below. Write an equation for L then state the x-
intercept of the graph and determine its interpretation in the context of the problem.

Answer 1

• L = - 8t + 80
• The x-intercept represents the time when the loan was paid off.

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According the graph

• The y-intercept is (0, 80) and x-intercept is (10, 0)

Slope-intercept equation

• y = mx + b, where m- the slope, b- the y-intercept

Find the slope

• m = (0 - 80)/(10 - ) = - 8

The line is

• L = - 8t + 80

The x-intercept (10 weeks) represents the time when the loan was paid off.