Solve the problem. When going more than 38 miles per hour, the gas mileage of a certain car fits the model where x is the speed of the car in miles per hour and y is the miles per gallon of gasoline. Based on this model, at what speed will the car average 15 miles per gallon? (Round to nearest whole number.)

73 mph

Step-by-step explanation:

The question seems to be incomplete because the model is missing, I found a similar question with the addition of the model, so if we can solve it (see attached image).

We have that the model would be:

y = 43.81 - 0.395 * x

We need to solve for x, if y = 15

Replacing:

15 = 43.81 - 0.395 * x

Solving for x we have:

0.395 * x = 43.81 - 15

0.395 * x = 28.81

x = 28.81 / 0.395

x = 72.9

We are asked to round to the nearest number therefore x = 73.

The car will average 15 miles per gallon at the speed of 73 miles per hour.

goog may have it for you

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225