7x^2+20x-2=0

Solution for 7x^2+20x-2=0 equation:

7x^2+20x-2=0

a = 7; b = 20; c = -2;
Δ = b2-4ac
Δ = 202-4·7·(-2)
Δ = 456
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:

$\sqrt{\Delta}=\sqrt{456}=\sqrt{4*114}=\sqrt{4}*\sqrt{114}=2\sqrt{114}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-2\sqrt{114}}{2*7}=\frac{-20-2\sqrt{114}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+2\sqrt{114}}{2*7}=\frac{-20+2\sqrt{114}}{14}
$