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

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

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

We add all the numbers together, and all the variables

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

We multiply parentheses

18i^2+15i=0

a = 18; b = 15; c = 0;
Δ = b2-4ac
Δ = 152-4·18·0
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15}{2*18}=\frac{-30}{36}
=-5/6
$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15}{2*18}=\frac{0}{36}
=0
$