To solve for x, you need to isolate/get the variable "x" by itself in the inequality:
12x + 7 < -11 Subtract 7 on both sides
12x + 7 - 7 < -11 - 7
12x < -18 Divide 12 on both sides to get "x" by itself
[tex]\frac{12x}{12} <\frac{-18}{12}[/tex]
[tex]x<\frac{-18}{12}[/tex] Simplify the fraction
[tex]x<\frac{-3}{2}[/tex] (x is any number less than -3/2)