Question

Alma charges $97 for a job that takes 2 hours and $187 for a job that takes 4 hours. Write an equation in slope-intercept form that gives the charge y in dollars for a job that takes x hours. Explain how you solved this problem.

Answer 1

y = 45x + 7

Explanation:

From the given data, we have ordered pairs (2, 97) and (4, 187). We can use them to find the slope, as such:

`m=(187-97)/(4-2)=(90)/(2)=45`

We can then use the slope and one of the ordered pairs to find the y-intercept, as such:

`y=mx+b\\97=45(2)+b\\97=90+b\\7=b`

Therefore, m = 45 and b = 7. We get the equation:

y = mx + b

y = 45x + 7