Solving right triangles geometry please helpp

What are the coordinates of the midpoint of ab? ,1/2) /2,-1) ,-3/2) /2,-2)

What is the value of m in the equation 1/2 m - 3/4n=16 when n=8

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?