55b^2-405b-280=0

Solution for 55b^2-405b-280=0 equation:

55b^2-405b-280=0

a = 55; b = -405; c = -280;
Δ = b2-4ac
Δ = -4052-4·55·(-280)
Δ = 225625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225625}=475$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-405)-475}{2*55}=\frac{-70}{110}
=-7/11
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-405)+475}{2*55}=\frac{880}{110}
=8
$