In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data
Y ===> midpoint of WZ
YZ = x + 3
WZ = 3x - 4
WZ = ?
Step 02:
YZ + YZ = WZ
(x + 3) + (x + 3) = 3x - 4
2x + 6 = 3x - 4
2x - 3x = - 4 - 6
-x = -10
x = -10 / -1
x = 10
WZ = 3x - 4
= 3(10) - 4
= 30 - 4
= 26
The answer is:
WZ = 26