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

The inequlaity is $\"\"$ .

Apply subtraction property of inequality: Subtract 18 from each side.

$\"\"$

$\"\"$ (Apply additive inverse property: $\"\"$ )

$\"\"$ (Apply additive identity property: $\"\"$ )

$\"\"$ (Subtract: $\"\"$ ) $\"\"$

Check:

To substitute a number less than 22 in $\"\"$ .

$\"\"$ (Substitute a = 21)

$\"\"$ (Add: 21 + 18 = 39)

The inequality is true $\"\"$

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