Final answer:
The equation of the line that describes the relationship between distance and time for Car X is y = 62x + b. The graph representing this relationship is a straight line with a positive slope of 62.
Step-by-step explanation:
a. The equation of the line that describes the relationship between distance and time for Car X can be expressed as y = mx + b, where y represents the distance in miles, x represents the time in hours, m represents the slope of the line, and b represents the y-intercept. In this case, Car X travels 186 miles in 3 hours, so we can determine the slope as m = 186/3 = 62. The equation becomes y = 62x + b.
b. The graph that represents the relationship between distance and time for Car X is a straight line with a positive slope of 62. The x-axis represents time in hours, and the y-axis represents distance in miles. The line starts at the y-intercept, which depends on the specific initial conditions of the car's position.