5b^2-36b-80=0

Solution for 5b^2-36b-80=0 equation:

5b^2-36b-80=0

a = 5; b = -36; c = -80;
Δ = b2-4ac
Δ = -362-4·5·(-80)
Δ = 2896
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2896}=\sqrt{16*181}=\sqrt{16}*\sqrt{181}=4\sqrt{181}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-4\sqrt{181}}{2*5}=\frac{36-4\sqrt{181}}{10}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+4\sqrt{181}}{2*5}=\frac{36+4\sqrt{181}}{10}
$