Question

The equation y = 8.5x - 77.5 is a linear model for data comparing the

speed that a car is going (x) to the stopping distance it takes for the car to stop
(y). Speed is measured in mph and distance in feet. What is the average
stopping distance of a car going 45 mph?

Answer 1

305 feet

Explanation:

you only need to replace the given data into the equation.

the value (y) is the one you are being asked to find and (x) is the given one

so:

y=8.5(x)-77.5

y=8.5(45)-77.5

y=382.5-77.5

y=305

since the units are given, you instantly know that y=305feet

Answer 2

The average stopping distance is 705 feet.

Explanation:

The given equation is

`y=8.5x-77.5`

Observe that the the ratio of change is 8.5 and the y-intercept is at (0, -77.5).

Where
`x` is the speed and
`y` is the distance.

So, to find the average stopping distance of a car going at 45 mph, we just replace this value in the given equation

`y=8.5x-77.5\\y=8.5(45)-77.5\\y=382.5-77.5\\y=305`

Therefore, the distance is 705 feet.