Answer:
x = 25
Explanation:
Given the midpoint of two points (x1,y1) and (x2,y2) = ((x1 + x2) / 2, (y1 + y2) / 2))
Midpoint of (x,6) and (-9,14) = ((-9 + x) / 2, (14 + 6) / 2) = (8,10).
The y coordinates cancel out because the midpoints work, so we can set the x value of the first coordinate as a midpoint of the second coordinate.
(-9 + x)/2 = 8
×2 ×2
(-9 + x) = 16
-9 + x = 16
+9 +9
x - 9 + 9 = 16 + 9
x = 25
___________
We can test this answer by substituting our answer back into the midpoint formula.
x = 25 → ((-9 + x) / 2, (14 + 6) / 2) = (8,10)
((-9 + 25) / 2, (14 + 6) / 2)) = (16/2, 20/2) = (8,10)