The inequality is .

Apply subtraction property of inequality: Subtract 6 from each side.

  (Apply commutative property of addition: a + b = b + a)

        (Apply additive inverse property: )

               (Apply additive identity property: )

                       (Subtract: )

Apply multiplication property of inequality: Multiply each side by 5.

                    (Cancel common terms)

                        (Multiply: )

Graph the solution set on a number line.

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

Check:

To check, substitute a number less than 20 in .

            (Substitute y = 15)

                 (Divide: )

                        (Add: 6 + 3 = 9)

The inequality is true.

The inequality solution set is .