Samoy's car used 9 gallons to travel 400 miles. After the mechanic works on the car, it used 6 gallons of gasoline to travel 450 miles. If the price of the gasoline was
approximately $2 per gallon, how much, to the nearest cent per mile, did it cost to run
the car after the mechanic worked on it?

answer: (3,11) is your answer.

step-by-step explanation:

we have

using a graphing tool

see the attached figure

this is a quadratic equation (vertical parabola) open up

the vertex is a > vertex

the domain of the function is all real > interval (-∞,∞)

the range of the function is the > [-6.125,∞)

the function has two x->   and

the function is increasing over the > (0.25,∞)

the function is decreasing over the > (-∞,0.25)

-3.5 degrees per hour

step-by-step explanation:

find the unit rate:

-12   1/4 degrees           12.25 degrees

= - = -3.5 degrees per hour

      3   1/2 hours               3.5 hours