Question

Part A: Maria rented a coat at $285 for 3 days. If she rents the same coat for 6 days, she has to pay a total rent of $510. Write an equation in the standard form to represent the total rent (y) that Maria has to pay for renting the coat for x days.
Part B: Write the equation obtained in Part A using function notation.

Part C: Describe the steps to graph the equation obtained above on the coordinate axes. Mention the labels on the axes and the intervals.

Answer 1

First to make the equation you need to make the ordered pairs that will come out to be (3,285) and (6,510) 
Second you plug those ordered pairs in the slope formula, you will end with 
510-285     225
-----------=  -------- = 75 that's your slope
   6-3           3
Now you plug it in the point slope form
y-285=75(x-3)
y-285=75x-225
  +285      +285
-----------------------
y=75x+60 is your equation 
f(x)=75x+60 in function notation
Part C: to graph the equation you can start off by making a table where you plug in -2,-1,0,1,2 into the equation for x or if you need to do more depends on your problem.Your labels for the x-axis would be the number of days and your y-axis would be the cost of rent after x number of days.