The inequality is

Apply division property of inequality: Divide each side by 3.

            (Cancel common terms)

                 (Divide:)

Graph the solution set on a number line.

Note: A dot means that this point is included in the solution set.

Check:

To check, substitute a number greater than or equal to 7  in .

        (Substitute )

            (Multiply: )

The inequality is true.

The inequality solution set is .