step 1
Solve the inequality
[tex]\begin{gathered} 3x+8\leq11 \\ 3x\leq11-8 \\ 3x\leq3 \\ x\leq1 \end{gathered}[/tex]
the solution for the first inequality is the interval
(-infinite, 1]
step 2
Solve the inequality
[tex]\begin{gathered} 3x+8\text{ > 20} \\ 3x\text{ > 20-8} \\ 3x\text{ > 12} \\ x\text{ > 4} \end{gathered}[/tex]
the solution for the second inequality is the interval
(4, infinite)
step 3
the general solution for the first inequality or the second inequality is
(-infinite, 1] U (4, infinite)
see the attached figure to better understand the problem
