-8x^2+139x+81=0

Solution for -8x^2+139x+81=0 equation:

-8x^2+139x+81=0

a = -8; b = 139; c = +81;
Δ = b2-4ac
Δ = 1392-4·(-8)·81
Δ = 21913
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(139)-\sqrt{21913}}{2*-8}=\frac{-139-\sqrt{21913}}{-16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(139)+\sqrt{21913}}{2*-8}=\frac{-139+\sqrt{21913}}{-16}
$