Question

Express the given complex number in the form $a+ib:$$\left(5i\right)(-\frac{3}{5}i)$

Answer 1

$\left(5i\right)\left(\frac{-3}{5}i\right)=(5\times \frac{-3}{5})\times (i\times i)$
$=-3i^2=-3(-1)=3,[\because i^2=-1]$
Which is clearly of the form $a+ib$ where, $a=3$ and $b=0$