Find an equation for the perpendicular bisector of the line segment whose endpoints are (9,4) and (3,-8)

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

The clayton family’s pool has vertices at the coordinates (0, 2), (0, 5), (2, 5), (2, 6), (5, 6), (5, 1), (2, 1), and (2, 2). if each grid square has an area of 9 square feet, what is the area of the pool?

What is the anwers for 9+2x=5x-3-x