The percentage of battery remaining after a certain number of hours after a cellphone is turned on can be represented by the graph shown.

Graph with x axis labeled number of hours and y axis labeled percent of battery remaining, with line that passes through the points 0 comma 100 and 2 comma 50 and 4 comma 0.

Part A: Write an equation in slope-intercept form to describe the relationship in the graph. (2 points)

Part B: Explain how you determined the equation. (1 point)

Part C: What is the meaning of the slope in the given situation? (1 point)