0=2x^2+8x-1020

Solution for 0=2x^2+8x-1020 equation:

0=2x^2+8x-1020

We move all terms to the left:

0-(2x^2+8x-1020)=0

We add all the numbers together, and all the variables

-(2x^2+8x-1020)=0

We get rid of parentheses

-2x^2-8x+1020=0

a = -2; b = -8; c = +1020;
Δ = b2-4ac
Δ = -82-4·(-2)·1020
Δ = 8224
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:

$\sqrt{\Delta}=\sqrt{8224}=\sqrt{16*514}=\sqrt{16}*\sqrt{514}=4\sqrt{514}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-4\sqrt{514}}{2*-2}=\frac{8-4\sqrt{514}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+4\sqrt{514}}{2*-2}=\frac{8+4\sqrt{514}}{-4}
$