Explain how to check if a point is on a line

Find the distance between the point (-3,-4), and (see the picture below)

Find the root(s) of f (x) = (x- 6)2(x + 2)2.

Adolphin is swimming with her friend. the dolphin jumps to a height of 4.54.54, point, 5 meters above the surface of the water as her friend swims 9.89.89, point, 8 meters directly below her. what is the position of the dolphin's friend relative to the surface of the water? meters