Let the equation of a plane

(1)

Direction ratios of parallel planes are related to each other as

Putting the values from the equation of a given parallel plane,

Putting values in equation (1), we have

(2)

A plane passes through (a,b,c) then it must satisfy the equation of a plane

λ(a.1 + b.1 + c.1)=d

λ(a + b + c)=d

Putting value in equation (2)