$\"\"$

The expression is $\"\"$ .

1) Multiply numerator and denominator by $\"\"$ because $\"\"$ is the conjugate of $\"\"$ .

$\"\"$

Apply difference of two square: $\"\"$ .

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

Apply FOIL method: $\"\"$ . \ \

$\"\"$

Take out common factor from nominator by negative 3.

$\"\"$

The simplified expression is $\"\"$ .