Answer:
Step-by-step explanation:
Let
x -----> the number of days
y ----> the total cost in dollars,
we know that
The equation of a linear function in slope intercept form is equal to
where
m is the slope o rate of the linear equation
b is the y-coordinate of the y-intercept
Remember that the y-intercept is the value of y when the value of x is equal to zero
In this problem we have
The slope is equal to the rental cost per day
so
When the number of days is equal to zero (x=0) the total cost is equal to $40 (administrative fee for the cleaning and maintenance of the car)
The y-intercept is the point (0,40)
so
substitute the values