Give all real solutions of the following equation:
$\left \{ -3, -2, 2, 3\right \}$
$\left \{ -3,3\right \}$
$\left \{ -3, -2\right \}$
$\left \{ 2,3\right \}$
$\left \{ -2,2\right \}$
$\left \{ -9,-4,4,9\right \}$
The equation has no real solutions.
$\left \{ 2, 3\right \}$
$\left \{ 4,9\right \}$
