For any service call, an electrician charges $60, plus $40 for each hour of labor. How much would the electrician charge for a service call that needs 4 hours of labor?

For any service call, an electrician charges $60, plus $40 for each hour of labor. How much would the electrician charge for a service call that needs 20 hours of labor? 
For any service call, an electrician charges $60, plus $40 for each hour of labor. Identify the points that are solutions (ON THE LINE) for this situation.
What is the slope of the line? What does it represent?

A flower shop allows you to purchase additional flowers, x, to add to the total cost of your arrangement, y. The line representing the relationship between x and y has a slope of 2.75 and a y-intercept of 25.25. Explain what the slope and y-intercept represent in this situation.
For each real-world situation, choose the graph that best represents it. y represents the total amount earned and x represents the number of hours worked. The slope of the line representing the relationship between x and y is 9.
Y represents the cost of a scoop of ice cream and x represents the cost of each topping. The slope of the line representing the relationship between y and y is 4.
Y represents the perimeter of a square and x represents its side length. The slope of the line representing the relationship between x and y is 0.25.
Y represents the cost of a mailing a 1-ounce package and x represents the cost added for each additional ounce. The slope of the line representing the relationship between x and y is 0.40.