2x^2+4x=720

Solution for 2x^2+4x=720 equation:

2x^2+4x=720

We move all terms to the left:

2x^2+4x-(720)=0

a = 2; b = 4; c = -720;
Δ = b2-4ac
Δ = 42-4·2·(-720)
Δ = 5776
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5776}=76$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-76}{2*2}=\frac{-80}{4}
=-20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+76}{2*2}=\frac{72}{4}
=18
$