x^2-39x-126=0

Solution for x^2-39x-126=0 equation:

x^2-39x-126=0

a = 1; b = -39; c = -126;
Δ = b2-4ac
Δ = -392-4·1·(-126)
Δ = 2025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2025}=45$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-39)-45}{2*1}=\frac{-6}{2}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-39)+45}{2*1}=\frac{84}{2}
=42
$