Final answer:
The equation y = -4x + 50 represents the relationship between time (x) and speed (y) of a car. The slope of the line is -4, indicating a decrease in speed over time. The y-intercept of 50 represents the initial speed of the car.
Step-by-step explanation:
The equation y = -4x + 50 represents the relationship between time (x) and speed (y) of a car. The equation is in the form y = mx + b, where m represents the slope of the line and b represents the y-intercept. In this equation, the slope is -4, meaning that for every one unit increase in time, the speed decreases by 4 units. The y-intercept is 50, which indicates that when the time is 0, the speed is 50 mph.