Which equation is modeled by the graph? using the equation, about how many more cars are in the deck at 9: 00 a. m. than at 8: 30 a. m.?
a) y = 3x + 50; 90 cars
b) y = 4x + 50; 75 cars
c) y = x + 50; 100 cars
d) y = 3x - 50; 120 cars

The correct answer is Choice A.

You can see from the graph that the y-intercept is 50 because it cross on the left at 50.

To find the slope, we can use the following two points (0, 50) and (20, 110). This will give a slope of 3.

Put the 50 and 3 together and you will have the equation:
y = 3x + 50