Answer:

Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a direct variation if it can be expressed in the form
or 
In this problem
Let
x------> the number of gallons
y------> the number of miles
the relationship between the number of miles and the gallons of gas represent a linear direct variation
The constant of proportionality k is equal to the slope m

therefore
the equation of the linear equation
