A rental truck costs $50 plus $0.40 per mile.

Write an equation that gives the cost of driving the truck x miles
Use the intersection of graphs method to determine the number of miles that the truck is driven if the rental cost is $70.

cost = 50 + .4x

set 50 + .4x = 70
and solve for x

To write an equation that gives the cost of driving the truck x miles, we can use the information provided: a rental truck costs $50 plus $0.40 per mile.

The equation can be represented as: Cost = 50 + 0.40x, where x is the number of miles driven and Cost represents the total cost.

To determine the number of miles that the truck is driven if the rental cost is $70, we can set up an equation by equating the total cost to $70:

70 = 50 + 0.40x

Now, we can solve this equation to find the value of x.

First, we need to isolate the variable x by subtracting 50 from both sides of the equation:

70 - 50 = 50 + 0.40x - 50

20 = 0.40x

To isolate x, we can divide both sides of the equation by 0.40:

x = 20 / 0.40

Simplifying,

x = 50

Therefore, the truck is driven 50 miles if the rental cost is $70.