x^2-130x-900=0

Solution for x^2-130x-900=0 equation:

x^2-130x-900=0

a = 1; b = -130; c = -900;
Δ = b2-4ac
Δ = -1302-4·1·(-900)
Δ = 20500
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:

$\sqrt{\Delta}=\sqrt{20500}=\sqrt{100*205}=\sqrt{100}*\sqrt{205}=10\sqrt{205}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-130)-10\sqrt{205}}{2*1}=\frac{130-10\sqrt{205}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-130)+10\sqrt{205}}{2*1}=\frac{130+10\sqrt{205}}{2}
$