Answer:
![c=20d+15](https://img.qammunity.org/2020/formulas/mathematics/high-school/ztx8eq7uatce0nr0cohg7opt2rqtkdjdkx.png)
Explanation:
Let
d ------> the length of the rental in days
c -----> the total cost to rent in dollars
we know that
The linear equation that represent this situation is
![c=20d+15](https://img.qammunity.org/2020/formulas/mathematics/high-school/ztx8eq7uatce0nr0cohg7opt2rqtkdjdkx.png)
This is the equation of the line in slope intercept form
where
The slope m is
![m=20\ (\$)/(day)](https://img.qammunity.org/2020/formulas/mathematics/high-school/ntqo1guqkkxydny17jkrqtpmwwtrd8ihzn.png)
The c-intercept b (value of c when the value of d is zero) is
![b=\$15](https://img.qammunity.org/2020/formulas/mathematics/high-school/s44tlm8dmn8002j865kqutepskdzl024vj.png)