Given: The equations of the parallel planes are 2x – 3y + 6z = 5 and 6x – 9y + 18z + 20 = 0
To find: distance between the planes
Formula Used: Distance between two parallel planes ax + by + cz + d1 = 0 and ax1 + by1 + cz1 + d1 = 0 is

Explanation:
The equations of the parallel planes are:
2x – 3y + 6z – 5 = 0
2x - 3y + 6x + \(\frac{20}3\) = 0
Therefore distance between them is

Therefore distance between the planes is \(\frac{5}3\) units