To find the x coordinate of the midpoint, we add the x coordinates of the endpoints together and divide by 2. We do not know the x coordinate of a so I will call it x
( x+3) /2 = -1
Multiply each side by 2
( x+3)/2 *2 = -1*2
x+3 = -2
Subtract 3 from each side
x+3-3 = -2-3
x = -5
The x coordinate of A is -5
We do the same thing for y
To find the y coordinate of the midpoint, we add the x coordinates of the endpoints together and divide by 2. We do not know the x coordinate of a so I will call it y
(y+-5) /2 = 2
Multiply each side by 2
(y-5)/2 *2 = 2*2
y-5 = 4
Add 5 to each side
y-5+5 = 4+5
y = 9
The y coordinate of A is 9
The coordinates of point A is ( -5,9)