Question

Point M (5,-7) is the midpoint of the line segment CD. If C is (2, "-3)," which of these are the coordinates of D?

Answer 1

D(8, -11)

Explanation:

You want the coordinates of end point D if C is (2, -3) and the midpoint of CD is M(5, -7).

Midpoint

The midpoint is the average of the endpoint coordinates:

M = (C +D)/2

Solving for D, we find ...

D = 2M -C

End point

Then point D is ...

D = 2(5, -7) -(2, -3) = (2·5-2, 2(-7)+3)

D = (8, -11)