-10s(s+5)=-129

Solution for -10s(s+5)=-129 equation:

-10s(s+5)=-129

We move all terms to the left:

-10s(s+5)-(-129)=0

We add all the numbers together, and all the variables

-10s(s+5)+129=0

We multiply parentheses

-10s^2-50s+129=0

a = -10; b = -50; c = +129;
Δ = b2-4ac
Δ = -502-4·(-10)·129
Δ = 7660
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{7660}=\sqrt{4*1915}=\sqrt{4}*\sqrt{1915}=2\sqrt{1915}$
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-50)-2\sqrt{1915}}{2*-10}=\frac{50-2\sqrt{1915}}{-20}
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-50)+2\sqrt{1915}}{2*-10}=\frac{50+2\sqrt{1915}}{-20}
$