Find equations of the planes \( P_{1}, P_{2} \), and \( P_{3} \) that are parallel to the coordinate planes and pass through the corner \( (9,10,11) \) of the box shown in the accompanying figure.
\( P_{1}: \) \( \square \)
\( P_{2} \) \( \square \)
\( P_{3}: \) \( \square \)