We need to verify if the given value is a solution to the equation. For that we will replace theta by the given value and verify if we find -1 on the left side.
[tex]\begin{gathered} 3\sqrt[]{2}\cdot\cos (\frac{3\pi}{4})+2 \\ 3\sqrt[]{2}\cdot(\frac{-1}{\sqrt[]{2}})+2_{} \\ -3+2 \\ -1 \end{gathered}[/tex]
Since we found "-1". The answer is True.
