D is the midpoint of CE, C has coordinates (-4,-12), and coordinates (15,-15). Find the coordinates of E.

midpoint formula : (x1 + x2) / 2, (y1 + y2) / 2

(-3,-2)x1 = -3 and y1 = -2

(x,y)x2 = x and y2 = y

now we sub

(-3 + x) / 2, (-2 + y) / 2

(-3 + x) / 2 = 2 1/2

-3 + x = 5/2 * 2

-3 + x = 5

x = 5 + 3

x = 8

(-2 + y) / 2 = 1

-2 + y = 1 * 2

-2 + y = 2

y = 2 + 2

y = 4

so the coordinates of point C are : (8,4)

Explanation: