Question:
Simplify each of the following and express it in the form a + ib
$(3+4 i)(2-3 i)$
Solution:
Given: $(3+4 i)(2-3 i)$
Firstly, we open the brackets
$3 \times 2+3 \times(-3 i)+4 i \times 2-4 i \times 3 i$
$=6-9 i+8 i-12 i^{2}$
$=6-i-12(-1)\left[\because, i^{2}=-1\right]$
$=6-i+12$
$=18-i$
