Three Dimensional Geometry Part 1

Given equation of a plane is
x−2y+2z−5=0
So, Equation of parallel plane is given by
x−2y+2z+d=0
Now, it is given that distance from origin to the parallel planes is 1 .
∴|‌

d

√12+22+23

‌

‌

|=1⇒d=±3
So equation of required plane
x−2y+2z±3=0