9k2-86k-40=0

Solution for 9k2-86k-40=0 equation:

9k^2-86k-40=0

a = 9; b = -86; c = -40;
Δ = b2-4ac
Δ = -862-4·9·(-40)
Δ = 8836
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8836}=94$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-86)-94}{2*9}=\frac{-8}{18}
=-4/9
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-86)+94}{2*9}=\frac{180}{18}
=10
$