I'm assuming you need to evaluate/simplify the equation, so you need to isolate/get x by itself in the equation:
2(3x + 1) = 11 Divide by 2 on both sides
3x + 1 = [tex]\frac{11}{2}[/tex] [11/2 or 5.5] Subtract by 1 on both sides
[tex]3x=\frac{11}{2}-\frac{2}{2}[/tex] [make the denominator the same to combine fractions]
3x = [tex]\frac{9}{2}[/tex] Divide by 3 on both sides
x = [tex]\frac{9}{6}=\frac{3}{2}[/tex]