(3-6i)(-5-3i)=0

Solution for (3-6i)(-5-3i)=0 equation:

(3-6i)(-5-3i)=0

We add all the numbers together, and all the variables

(-6i+3)(-3i-5)=0

We multiply parentheses ..

(+18i^2+30i-9i-15)=0

We get rid of parentheses

18i^2+30i-9i-15=0

We add all the numbers together, and all the variables

18i^2+21i-15=0

a = 18; b = 21; c = -15;
Δ = b2-4ac
Δ = 212-4·18·(-15)
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-39}{2*18}=\frac{-60}{36}
=-1+2/3
$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+39}{2*18}=\frac{18}{36}
=1/2
$