x^2-14x-39=0

Solution for x^2-14x-39=0 equation:

x^2-14x-39=0

a = 1; b = -14; c = -39;
Δ = b2-4ac
Δ = -142-4·1·(-39)
Δ = 352
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:

$\sqrt{\Delta}=\sqrt{352}=\sqrt{16*22}=\sqrt{16}*\sqrt{22}=4\sqrt{22}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-14)-4\sqrt{22}}{2*1}=\frac{14-4\sqrt{22}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-14)+4\sqrt{22}}{2*1}=\frac{14+4\sqrt{22}}{2}
$