Answer: The linear function y = 60x + 90 can be used to model the relationship between the hours and costs of a repair.
Explanation:
In this model or function we will represent the number of hours by x and the cost by y.
Using that information we can generate two points , (8, 570) and (7,510)
Now to write a linear function we will need to find the slope which will be the cost per hour, and the y intercept which will be the initial amount .
To find the slope we will find the difference in the y coordinates of the points and divide it by the difference in the x coordinates.
570 - 510 = 60
8 - 7 = 1
Slope: 60 / 1 = 60
We will have to find the y intercept by using the formula y = mx + b.
We will input the x and y coordinates of a given point plus the slope into the formula to solve for b.
570 = 60(8) + b
570 = 480 + b
-480 -480
b = 90