Respuesta :

Hello!

Since D is the midpoint and the two equations are and both sides of point D the equations equal each other

9x - 7 = 3x + 17

Now you solve it algebraically

Add 7 to both sides

9x = 3x + 24

Subtract 3x from both sides

6x = 24

Divide both sides by 6

x = 4

Now we put this into both equations and add them

9(4) - 7 = 29
3(4) + 17 = 29

29 + 29 = 58

The answer is 58 units

Hope this helps!