Answer:
The coordinates of B are (-2 , 9)
Step-by-step explanation:
A (8, 4)
M (3 , -1)
To calculate a midpoint you have to add the corresponding coordinates of each point and divide them by 2
(Ax + Bx) / 2 = Mx
(8 + Bx) / 2 = 3
8 + Bx = 3 * 2
Bx = 6 - 8
Bx = -2
(Ay + By) / 2 = My
( -1 + By) / 2 = 4
-1 + By = 4 * 2
By = 8 + 1
By = 9
The coordinates of B are (-2 , 9)
