How do I put an imaginary number

i*(6+7i)

 

$${i}{\mathtt{\,\times\,}}\left({\mathtt{6}}{\mathtt{\,\small\textbf+\,}}{\mathtt{7}}{i}\right) = {\mathtt{\,-\,}}{\mathtt{7}}{\mathtt{\,\small\textbf+\,}}{\mathtt{6}}{i}$$

 

I just entered it - the calc automaticals takes i to be   $${\sqrt{-{\mathtt{1}}}}$$

Try this.

In the calculator for this site, switch to the Equation Solver. Here you can use the term "i". Remember that i^2=-1