XY and YZ are the same length, so we can set their expressions to equal each other:
(x+5) = (3x - 3)
Add 3 to both sides:
x + 8 = 3x
Subtract x from both sides:
2x = 8
Divide both sides by 2 to get x by itself:
x = 4
XZ is equal to the lengths of lines XY and YZ. Plug the x value into their expressions:
(4 + 5) + (3(4) - 3)
9 + (12 - 3)
9 + 9 = 18
The measure of line XZ will be 18.
