Answer:
D (- 7, 4 )
Explanation:
given endpoints (x₁, y₁ ) and (x₂, y₂ ) then the coordinates of midpoint (M) are
M = (
,
) ← midpoint formula
let (x₁, y₁ ) = C (3, 8 ) and (x₂, y₂ ) = D (x, y ) with M = (- 2, 6 )
use the midpoint formula and equate the x/y coordinates to the corresponding x/y coordinates of M , that is
= - 2 ( multiply both sides by 2 to clear the fraction )
3 + x = - 4 ( subtract 3 from both sides )
x = - 7
and
= 6 ( multiply both sides by 2 to clear the fraction )
8 + y = 12 ( subtract 8 from both sides )
y = 4
coordinates of D = (- 7, 4 )