Question

Gerri purchases a coupon book with discounts for her favorite coffee shop. Every coupon for the coffee shop offers the same discount. The table shows her total savings, y, based on the number of coupons, x, used from the book.

Answer 1

We need to find the slope and y-intercept. Firstly, let’s find the y-intercept. The y-intercept is where the line intercepts the y-axis, so the coordinate will be (0, y-intercept). According to the table, that would be (0, -20).

Next, we can find the slope by finding the change in y, and then dividing that by the change in x. In other words, y2-y1/x2-x1. Let’s pick two coordinates, (0, -20) and (5, -10). Once we plug in our numbers, we get -10-(-20)/5-0 which is 10/5 which is 2.

The y-intercept is (0, -20), and the slope is 2.