Points (-5,7) and (-9,1) are endpoints of the diameter of a circle. a) What is the length of the diameter?

Points (-5,7) and (-9,1) are endpoints of the diameter of a circle.

a) What is the length of the diameter? Give the exact answer, simplified as much as possible. (show work)

b) What is the center point C of the circle?

c) Given the point C you found in part (b), state the point symmetric to C about the x-axis.