Two races cars, Car X and car Y are at the starting point of a 2km track at the same time. car X and car Y make 1 lap every 60s and every 80s respectively. a. how long, in seconds, will it take for both cars to be back at the starting time at the same time?
b. How long, in minutes, will it take for the faster car to be 5 laps ahead of the slower car?

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.