Question

Point A is at (-2, -7) and point M is at (2.5, -1.5).

Point M is the midpoint of point A and point B.
What are the coordinates of point B?

Answer 1

Give more points

Explanation:

Answer 2

B = (7, 4)

Explanation:

B = 2M -A = 2(2.5, -1.5) -(-2, -7)

B = (5+2, -3+7)

B = (7, 4)

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Derivation

You know the midpoint is calculated from ...

M = (A+B)/2

Solving for B, we get ...

2M = A+B

B = 2M-A . . . . the formula we used above