Answer:
[tex]{ \underline{ \mathfrak{ \: answer : }}}[/tex]
• Note that in complex numbers, i² = -1
[tex]{ \rm{ \sqrt{ - 72} = \sqrt{ - 1 \times (4 \times 9 \times 2)} }} \\ \\ = { \rm{ \sqrt{ - 1} \times \sqrt{4} \times \sqrt{9} \times \sqrt{2} }} \\ \\ = { \rm{ \sqrt{( {i}^{2} )} \times 2 \times 3 \times \sqrt{2} }} \\ \\ = { \rm{i \times 6 \times \sqrt{2} }} \\ \\ { \boxed{ \boxed{ \rm{ \: \: answer= { \rm{6i \sqrt{2} }}}}}}[/tex]
