-3s^2-17s+56=0

Solution for -3s^2-17s+56=0 equation:

-3s^2-17s+56=0

a = -3; b = -17; c = +56;
Δ = b2-4ac
Δ = -172-4·(-3)·56
Δ = 961
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{961}=31$
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-17)-31}{2*-3}=\frac{-14}{-6}
=2+1/3
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+31}{2*-3}=\frac{48}{-6}
=-8
$