Question

Express each of the complex number given in the Exercises $1$ to $10$ in the form $a+ib$.
$\left(5i\right)(-\frac{3}{5}i)$

Answer 1

$i=\sqrt{-1}\Rightarrow i^2=-1$

$\left(5i\right)(-\frac{3}{5}i)$

$=5\times (-\frac{3}{5})\times i^2$

$=-3(-1)$

$=3+i\times 0$