X*(2x-4)=240

Solution for X*(2x-4)=240 equation:

X(2X-4)=240

We move all terms to the left:

X(2X-4)-(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
$