Answer:
x=6
XY=24 units
YZ=18 units
Step-by-step explanation:
we have that
Y is between X and Z
[tex]XZ=XY+YZ[/tex]
substitute the given values and solve for x
[tex]42=4x+3x\\42=7x\\x=6[/tex]
therefore
[tex]XY=4x=4(6)=24\ units\\YZ=3x=3(6)=18\ units[/tex]