Question

Paul made flyers to promote the grand opening of his bookstore. He gave 20 flyers to his friends, and then handed out 9 flyers every hour. He decides to graph the number of flyers, y, given out over x hours. Which equation best describes Paul's graph?

Answer 1

For this case, the first thing we must do is define variables.
 We have then:
 x: number of hours.
 y: number of flyers
 We now write the equation that represents this problem.
 We have then:
 y = 9x + 20
 The slope of the graph m = 9 represents the number of flyers distributed every hour.
 The intersection with the axis and b = 20 represents the number of flyers that Paul distributed to his friends.
 Answer:
 An equation that best describes Paul's graph is:
 y = 9x + 20

Answer 2

The correct equation is y = 9x + 20, where x is equal to the number of hours.

This is because at 0 hours of work, he still has the 20 handed out. This gives us the point of (0, 20).

At one hour we know he has handed out 9 more, giving us the point of (1, 29).

We can then use the slope formula to find the slope of the equation.
m = (y1 - y2)/(x1- x2)
m = (29-20)/(1-0)
m = 9/1
m = 9.

Then you can use 20 as the y intercept because the y intercept is when the x value equals 0. Use them in slope intercept form and you have y = 9x + 20.