$\"\"$ $\"\"$

The inequality is $\"\"$ .

Apply multiplication property of inequality: Multiply each side by

negative 3.

$\"\"$

$\"\"$ (Cancel common terms)

$\"\"$ (Multiply: $\"\"$ )

Graph the solution set on a number line $\"\"$

Check:

To check, substitute a number less than 21 in $\"\"$ .

$\"\"$

$\"\"$ (Divide: $\"\"$ ) $\"\"$

The inequality solution set is $\"\"$ .