Question

Given that point A is the midpoint of line segment ED, where E( -1,9) and A(4,5), what is the location of point D?

Answer 1

D(9, 1)

Explanation:

A being the midpoint means its coordinates satisfy ...

A = (E + D)/2

Solving for D, we find ...

D = 2A -E

= 2(4, 5) -(-1, 9) = (2·4 +1, 2·5 -9)

D = (9, 1)