Answer:
[tex]\large\boxed{a<-1\to a\in(-\infty,\ -1)\to\{a|a\in\mathbb{R}\ \wedge\ a<-1\}}[/tex]
Step-by-step explanation:
[tex]-5a+6>11\qquad\text{subtract 6 from both sides}\\\\-5a>5\qquad\text{change the signs}\\\\5a<-5\qquad\text{divide both sides by 5}\\\\a<-1\to a\in(-\infty,\ -1)\to\{a|a\in\mathbb{R}\ \wedge\ a<-1\}[/tex]