11y^2-78y-80=0

Solution for 11y^2-78y-80=0 equation:

11y^2-78y-80=0

a = 11; b = -78; c = -80;
Δ = b2-4ac
Δ = -782-4·11·(-80)
Δ = 9604
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9604}=98$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-78)-98}{2*11}=\frac{-20}{22}
=-10/11
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-78)+98}{2*11}=\frac{176}{22}
=8
$