x^2=-11x+80

Solution for x^2=-11x+80 equation:

x^2=-11x+80

We move all terms to the left:

x^2-(-11x+80)=0

We get rid of parentheses

x^2+11x-80=0

a = 1; b = 11; c = -80;
Δ = b2-4ac
Δ = 112-4·1·(-80)
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-21}{2*1}=\frac{-32}{2}
=-16
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+21}{2*1}=\frac{10}{2}
=5
$