Hi there!
Since the triangle is equilateral, all of its sides are congruent. This means that to solve, we can set the two given equations equal to each other.
2(x - 8) = 1/2x + 8
2x - 16 = 1/2x + 8
1.5x - 16 = 8
1.5x = 24
x = 16
Now that we know what x is, we can plug that in for x in the equation for ZY.
2(16 - 8) = ZY
ZY = 2(8)
ZY = 16 units
And here is the work to show that XZ is also 16.
1/2(16) + 8 = XZ
XZ = 8 + 8
XZ = 16
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!