Question

The equation y=−0.0088x2+0.79x+15 models the speed x (in miles per hour) and average gas mileage y (in miles per gallon) for a vehicle. What is the best approximate for the average gas mileage at a speed of 60 miles per hour?

Answer 1

30.72 miles per gallon is the best approximate for the average gas mileage at a speed of 60 miles per hour

Explanation:

Given the equation:

`y = -0.0088x^2+0.79x+15` ,....[1]

where,

y is the average gas mileage (in miles per gallon)

x is the speed (in miles per hour)

We have to find the the average gas mileage at a speed of 60 miles per hour.

⇒
`x = 60` miles per hour.

Substitute in [1] we have;

`y = -0.0088(60)^2+0.79(60)+15`

⇒
`y = -0.0088(3600)+47.4+15`

⇒
`y = -31.68+47.4+15`

Simplify:

y = 30.72 miles per gallon

Therefore, the best approximate for the average gas mileage at a speed of 60 miles per hour is, 30.72 miles per gallon

Answer 2

Answer: 30.72 miles per gallon

To find best approximate for the average gas mileage at a speed of 60 miles per hour you need to replace the variable x with 60. The calculation would be:

y=−0.0088x2+0.79x+15
y= -31.68 +47.4 + 15
y= 30.72