The cost of renting a car for a day is $0.50 per mile plus a $15 flat fee. (a) write an equation to represent this relationship. let x be the number of miles driven and y be the total cost for the day. (b) what does the graph of this equation form on a coordinate plane? explain. (c) what is the slope and the y - intercept of the graph of the relationship? explain.

ANSWER
a)

b) The graph represents a straight line.

c)

The y-intercept is

EXPLANATION

a) Let x be the number of miles driven and y be the total cost for the day.

Since there is a flat fee of $ 15, we can write the equation for the total cost as,

The flat fee is a constant or fixed amount you have to pay.

b) The graph of this equation form a straight line on a coordinate plane because the highest degree of the variables is one. See graph in attachment.

c) The slope of the graph is

The reason is that, the unit rate is $ 0.50 and the slope represents the rate of change of the graph.

The y-intercept is $15. The reason is that, you have to pay a flat fee, which is a fixed cost.

Therefore the graph starts from 15 on the y-axis which is called the y-intercept.

A.) y=.50x+15 
b.) a line that goes up and toward the right 
C.) half a unit up over one