3d Geometry

A plane \(E\) is perpendicular to the two planes \(2 x-2 y+z=0\) and \(x-y+2 z=4\), and passes through the point \(P(1,-1,1)\). If the distance of the plane \(E\) from the point \(Q(a, a, 2)\) is \(3 \sqrt{2}\), then \((P Q)^{2}\) is equal to :