The inequality is .

Apply addition property of inequality: If a < b then a + c < b + c.

           (Add 6 to each side)

                 (Apply additive inverse property: )

                       (Apply additive identity property: )

                            (Add: )

Graph the solution set on a number line.

Note: A circle means that this point is not included in the solution set.

Check:

To check the solution, substitute a number less than 19 in

                     (Substitute )

                           (Subtract: )

The inequality is true.

The inequality solution set is .