(D^2+4D+3.36I)y=0

Solution for (D^2+4D+3.36I)y=0 equation:

(^2+4+3.36)D=0

We multiply parentheses

D^2+4D+3.36D=0

We add all the numbers together, and all the variables

D^2+7.36D=0

a = 1; b = 7.36; c = 0;
Δ = b2-4ac
Δ = 7.362-4·1·0
Δ = 54.1696
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$D_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$D_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$D_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7.36)-\sqrt{54.1696}}{2*1}=\frac{-7.36-\sqrt{54.1696}}{2}
$
$D_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7.36)+\sqrt{54.1696}}{2*1}=\frac{-7.36+\sqrt{54.1696}}{2}
$