Q.

The equation of the plane which is parallel to the plane x-2y+2z=5 and whose distance from the point (1, 2, 3) is 1, is:

1 x-2y+2z=3  
2 x-2y+2z+3=0  
3 x-2y+2z=6  
4 x-2y+2z+6=0  

Ans.

(3)

Ans.      x-2y+2z=6

Explanation:

Equation of plane parallel to x-2y+2z=5 is

              x-2y+2z+k=0                          ...(i)

Now, according to question,

                1-4+6+k9=±1

or                         k+3=±3

⇒                                 k=0 or -6

∴        x-2y+2z-6=0

or               x-2y+2z=6