Question
$\text{If}\overrightarrow{\text{a}} = \hat{\text{i}} + 2\hat{\text{j}} + \hat{\text{k}}, \overrightarrow{\text{b}} = 2\hat{\text{i}} + \hat{\text{j}}$ and $\overrightarrow{\text{c}} = 3\hat{\text{i}} - 4\hat{\text{j}} - 5\hat{\text{k}},$ then find a unit vector perpendicular to both of the vectors $(\overrightarrow{\text{a}} - \overrightarrow{\text{b}}) \text{and} \overrightarrow{\text{(c}} - \overrightarrow{\text{b}}). $