Question 647946
If you draw a diagram you'll see that the length of XY plus the length of YZ = the length of XZ which is 28.  You are given the lengths of XY and YZ, so make an equation.
<P>
12+2x = 28  Subtract 12 from both sides<P>
2x = 16   Divide both sides by 2<P>
x = 8<P>
If x=8 then YZ = 2x = 2*8 = 16