x^2-91x+880=0

Solution for x^2-91x+880=0 equation:

x^2-91x+880=0

a = 1; b = -91; c = +880;
Δ = b2-4ac
Δ = -912-4·1·880
Δ = 4761
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4761}=69$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-91)-69}{2*1}=\frac{22}{2}
=11
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-91)+69}{2*1}=\frac{160}{2}
=80
$