0=-3x^2-120x

Solution for 0=-3x^2-120x equation:

0=-3x^2-120x

We move all terms to the left:

0-(-3x^2-120x)=0

We add all the numbers together, and all the variables

-(-3x^2-120x)=0

We get rid of parentheses

3x^2+120x=0

a = 3; b = 120; c = 0;
Δ = b2-4ac
Δ = 1202-4·3·0
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(120)-120}{2*3}=\frac{-240}{6}
=-40
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(120)+120}{2*3}=\frac{0}{6}
=0
$