P is a plane passing through the intersection of P1 and P2. Equation of P:P1+λP2=0 (x+y+4z−16)+λ(−x+y+z−6)=0 ...(i) Since plane P passes through (1,2,3), then (1+2+12−16)+λ(−1+2+3−6)=0 ⇒−1+λ(−2)=0 ⇒λ=
−1
2
On putting λ=
−1
2
in Eq. (i), we get P:3x+y+7z−26=0 Clearly (4,2,2) not lie on the plane.