$$\\\frac{\sqrt{-40}}{\sqrt{4}}\\\\
=\sqrt{-10}\\\\
=\sqrt{10*-1}\\\\
=\sqrt{10}*\sqrt{-1}\\\\
=\sqrt{10}\;i\\\\$$
This is not a real number.
There are no real solutions since no number multiplied by itself = a neg number
This is an 'imaginary number'