Distance between two parallel planes Ax + By + Cz = d₁ and Ax + By + Cz = d₂ is

⇒

Given -

First Plane is

2x + 3y + 4z = 4

Comparing with Ax + By + Cz = d₁, we get -

A = 2, B = 3, C = 4, d₁ = 4

Second Plane is

4x + 6y + 8z = 12

After Dividing by 2,

2x + 3y + 4z = 6

Comparing with Ax + By + Cz = d₁, we get -

A = 2, B = 3, C = 4, d₂ = 6

So,

Distance between two planes

= 2/√29

Hence, (D) is the correct option.