We know that line WJL is a straight line, so all angles formed on it add up to [tex]\ang{180}[/tex].
We know that angle WJH is [tex]\ang{18}[/tex] and angle HJG is [tex]\ang{90}[/tex] (right angle), so that leaves angle GJL to be:
[tex]18 + 90 + GJL = 180[/tex]
[tex]108 + GJL = 180[/tex]
[tex]GJL = 72[/tex]
Now we can solve for [tex]x[/tex]:
[tex]GJL = 9x = 72[/tex]
[tex]9x = 72[/tex]
[tex]x = \frac{72}{9}[/tex]
[tex]x = 8[/tex]
