Ответ:

\((3\sqrt2)^2=18\), \((4\sqrt2)^2=32\).

\(\dfrac{18}{5}-\dfrac{32}{10}=\dfrac{18}{5}-\dfrac{16}{5}=\dfrac{2}{5}=0.4\).

Ответ: \(\dfrac{2}{5}\) или \(0,4\).