X=(-5i)(-4i)

Solution for X=(-5i)(-4i) equation:

X=(-5X)(-4X)

We move all terms to the left:

X-((-5X)(-4X))=0

We multiply parentheses ..

-((+20X^2))+X=0


We calculate terms in parentheses: -((+20X^2)), so:

(+20X^2)

We get rid of parentheses

20X^2

Back to the equation:

-(20X^2)


a = -20; b = 1; c = 0;
Δ = b2-4ac
Δ = 12-4·(-20)·0
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-1}{2*-20}=\frac{-2}{-40}
=1/20
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+1}{2*-20}=\frac{0}{-40}
=0
$