Answer:
Part 1) 
Par 2) see the explanation
Part 3) 
Step-by-step explanation:
Part 1) Write an equation in slope intercept form to represent this problem
Let
x ----> the number of tickets
y ---> the total cost
The linear equation in slope intercept form is equal to
where
m is the slope or unit rate
b is the y-intercept (one-time processing fee)
In this problem we have

ordered pairs (4,141.95) and (7,239.45)
Find the slope
The formula to calculate the slope between two points is equal to

substitute the values in the formula



substitute the values in the linear equation

Part 2) What does your slope represent in this problem? What does your y-intercept represent in this problem?
a) The slope of the linear equation represent the unit rate, so the slope represents the cost of one ticket

b) The y-intercept is the value of y when the value of x is equal to zero
In this context, the y-intercept represent the one-time processing fee

Part 3) Use the equation to find how much Alan would have to pay for 12 tickets
For x=12 tickets
substitute in the linear equation

