Q.
A plane passes through (1,−2,1) and is perpendicular to two planes 2x−2y+z=0 and x−y+2z=4, then the distance of the plane from the point (1,2,2) is.
D.R. of the normal to the plane that that is perpendicular to the plane 2x−2y+z=0 and x−y+2z=4 is given by ∣∣i^21j^−2−1k^12∣∣=−3i^−3j^ or i^+j^
So the required plane passing through (1,−2,1) is (x−1)+(y+2)=0 or x+y+1=0
Hence the distance of (1,2,2) form this plane is d=24=22 units