2x^2+14x-255=0

Solution for 2x^2+14x-255=0 equation:

2x^2+14x-255=0

a = 2; b = 14; c = -255;
Δ = b2-4ac
Δ = 142-4·2·(-255)
Δ = 2236
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2236}=\sqrt{4*559}=\sqrt{4}*\sqrt{559}=2\sqrt{559}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(14)-2\sqrt{559}}{2*2}=\frac{-14-2\sqrt{559}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+2\sqrt{559}}{2*2}=\frac{-14+2\sqrt{559}}{4}
$