x(2x+2)=480

Solution for x(2x+2)=480 equation:

x(2x+2)=480

We move all terms to the left:

x(2x+2)-(480)=0

We multiply parentheses

2x^2+2x-480=0

a = 2; b = 2; c = -480;
Δ = b2-4ac
Δ = 22-4·2·(-480)
Δ = 3844
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3844}=62$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-62}{2*2}=\frac{-64}{4}
=-16
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+62}{2*2}=\frac{60}{4}
=15
$