(x)(6+x)=520

Solution for (x)(6+x)=520 equation:

(x)(6+x)=520

We move all terms to the left:

(x)(6+x)-(520)=0

We add all the numbers together, and all the variables

x(x+6)-520=0

We multiply parentheses

x^2+6x-520=0

a = 1; b = 6; c = -520;
Δ = b2-4ac
Δ = 62-4·1·(-520)
Δ = 2116
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2116}=46$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-46}{2*1}=\frac{-52}{2}
=-26
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+46}{2*1}=\frac{40}{2}
=20
$