The equation is y=-3x+23. The relationship between the number of tricks and biscuits left shows that after every trick the number of biscuits decreases by 3 and thus when no trick is done there are 23 biscuits. The independent variable is the number of tricks and dependent variable is the number of biscuits left.
Work Step by Step
The slope of the graph is -3 because the amount of biscuits left after every trick is decreased by 3. Also at 0 tricks the number of biscuits is 23 because when x is 1, y is 20 and thus when x is 0, y is 23 which shows that (0,23) is the y- intercept.