Circle O is located on the coordinate plane with center at (2,3). One endpoint of a diameter is at (-1,-1). What are the coordinates of the other endpoint of this diameter? Express your answer as an ordered pair.
Notice that (2,3) will be the mid-point of both diameter endpoints
So..let (x, y) be the other diameter endpoint....and we have
(x + - 1) / 2 = 2 and (y + -1) / 2 = 3
multiply both sides by 2
x - 1 = 4 y - 1 = 6
add 1 to both sides
x = 5 y = 7
So the other endpoint is (5, 7)