Let be the number of times Tony drives to visit his grandma, and let represent the amount of change Tony has in his car.
Since he pays $1.25 in tolls every time he visit his grandma, the amount of change in his car is going to decrease by $1.25 every visit. We know form our problem that he initially has 6 dollars in change in his car. Since represents the amount of change and the number of visits, we can relate all the variables and quantities using a linear equation:
To graph our linear equation, we just need to find two points and join them with a line.
The easiest points we can find are the and -intercepts.
- To find the we just need to replace with zero and solve for :
So, our first point is (0,6)
- To find the we just need to replace with zero and solve for :
Our second point is (4.8,0)
Now we can join those two points with a line.
we can conclude that the graph that represents the change Tony has in his car is the one in the picture: