How do you find a segment endpoint if you are given one end point of(12,-8)and a midpoint of (3,18)

How is working backward similar to solving an equation?

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance

Jordan got 27 out of 90 correct on his test . what fraction of the marks did her get correct