560+240x-20x^2=0

Solution for 560+240x-20x^2=0 equation:

560+240x-20x^2=0

a = -20; b = 240; c = +560;
Δ = b2-4ac
Δ = 2402-4·(-20)·560
Δ = 102400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{102400}=320$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(240)-320}{2*-20}=\frac{-560}{-40}
=+14
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(240)+320}{2*-20}=\frac{80}{-40}
=-2
$