(9-4i)(8-2i)=0

Solution for (9-4i)(8-2i)=0 equation:

(9-4i)(8-2i)=0

We add all the numbers together, and all the variables

(-4i+9)(-2i+8)=0

We multiply parentheses ..

(+8i^2-32i-18i+72)=0

We get rid of parentheses

8i^2-32i-18i+72=0

We add all the numbers together, and all the variables

8i^2-50i+72=0

a = 8; b = -50; c = +72;
Δ = b2-4ac
Δ = -502-4·8·72
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-50)-14}{2*8}=\frac{36}{16}
=2+1/4
$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-50)+14}{2*8}=\frac{64}{16}
=4
$