Hello!
Let's solve this inequality for [tex]\sf{x}.[/tex]
[tex]\\[/tex]
[tex]\begin{aligned} \sf{9(2x+1) < 9x-18}\\\sf{18x+9 < 9x-18}\\\sf{18x-9x < -18-9}\\\sf{9x < -27}\\\sf{x < -3\:is\:in\:the\:solution\:set.} \end{aligned}[/tex]
Hope that helps! :)
-art lover