X^2-2x-86=0

Solution for X^2-2x-86=0 equation:

X^2-2X-86=0

a = 1; b = -2; c = -86;
Δ = b2-4ac
Δ = -22-4·1·(-86)
Δ = 348
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:

$\sqrt{\Delta}=\sqrt{348}=\sqrt{4*87}=\sqrt{4}*\sqrt{87}=2\sqrt{87}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-2\sqrt{87}}{2*1}=\frac{2-2\sqrt{87}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+2\sqrt{87}}{2*1}=\frac{2+2\sqrt{87}}{2}
$