2x(x-2)=240

Solution for 2x(x-2)=240 equation:

2x(x-2)=240

We move all terms to the left:

2x(x-2)-(240)=0

We multiply parentheses

2x^2-4x-240=0

a = 2; b = -4; c = -240;
Δ = b2-4ac
Δ = -42-4·2·(-240)
Δ = 1936
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1936}=44$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-44}{2*2}=\frac{-40}{4}
=-10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+44}{2*2}=\frac{48}{4}
=12
$