Answer:
D(-11, -2)
Step-by-step explanation:
You want the coordinates of point D so that ABCD is a parallelogram, given A(-4, -5), B(6, 1), C(-1, 4).
Midpoint
The midpoints of the diagonals are the same point:
(A +C)/2 = (B +D)/2
A +C = B +D . . . . . . . multiply by 2
D = A +C -B . . . . . . solve for D
D = (-4, -5) +(-1, 4) -(6, 1) = (-4 -1 -6, -5 +4 -1) = (-11, -2)
The coordinates of point D are (-11, -2).
