2x^2+4x-82=0

Solution for 2x^2+4x-82=0 equation:

2x^2+4x-82=0

a = 2; b = 4; c = -82;
Δ = b2-4ac
Δ = 42-4·2·(-82)
Δ = 672
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:

$\sqrt{\Delta}=\sqrt{672}=\sqrt{16*42}=\sqrt{16}*\sqrt{42}=4\sqrt{42}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-4\sqrt{42}}{2*2}=\frac{-4-4\sqrt{42}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+4\sqrt{42}}{2*2}=\frac{-4+4\sqrt{42}}{4}
$