x^2-20x-49=0

Solution for x^2-20x-49=0 equation:

x^2-20x-49=0

a = 1; b = -20; c = -49;
Δ = b2-4ac
Δ = -202-4·1·(-49)
Δ = 596
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:

$\sqrt{\Delta}=\sqrt{596}=\sqrt{4*149}=\sqrt{4}*\sqrt{149}=2\sqrt{149}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-2\sqrt{149}}{2*1}=\frac{20-2\sqrt{149}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+2\sqrt{149}}{2*1}=\frac{20+2\sqrt{149}}{2}
$