Question

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

Answer 1

$\left(5i\right)(-\frac{3i}{5})=-3i^2=-3(-1)[\because i^2=-1]=3=3+i\left(0\right)$

Comparing with a+ib,

$a=3,b=0$

Therefore, $3+i\left(0\right)$