(120+x)(180+x)=0

Solution for (120+x)(180+x)=0 equation:

(120+x)(180+x)=0

We add all the numbers together, and all the variables

(x+120)(x+180)=0

We multiply parentheses ..

(+x^2+180x+120x+21600)=0

We get rid of parentheses

x^2+180x+120x+21600=0

We add all the numbers together, and all the variables

x^2+300x+21600=0

a = 1; b = 300; c = +21600;
Δ = b2-4ac
Δ = 3002-4·1·21600
Δ = 3600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3600}=60$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(300)-60}{2*1}=\frac{-360}{2}
=-180
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(300)+60}{2*1}=\frac{-240}{2}
=-120
$