x^2-2x=3969

Solution for x^2-2x=3969 equation:

x^2-2x=3969

We move all terms to the left:

x^2-2x-(3969)=0

a = 1; b = -2; c = -3969;
Δ = b2-4ac
Δ = -22-4·1·(-3969)
Δ = 15880
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:

$\sqrt{\Delta}=\sqrt{15880}=\sqrt{4*3970}=\sqrt{4}*\sqrt{3970}=2\sqrt{3970}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-2\sqrt{3970}}{2*1}=\frac{2-2\sqrt{3970}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+2\sqrt{3970}}{2*1}=\frac{2+2\sqrt{3970}}{2}
$