Problems from Distance between two planes in space

Development:

To calculate the distance between the planes $\pi$ and ${\pi }^{\prime }$ we can apply: $$\text{d}(\pi ,{\pi }^{\prime })={\displaystyle \frac{|D-D|}{\sqrt{A^2+B^2+C^2}}}={\displaystyle \frac{|-4-1|}{\sqrt{1+9+6}}}={\displaystyle \frac{5}{4}}$$

Solution:

$\text{d}(\pi ,{\pi }^{\prime })={\displaystyle \frac{5}{4}}$

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