9+s(1-2s)=0

Solution for 9+s(1-2s)=0 equation:

9+s(1-2s)=0

We add all the numbers together, and all the variables

s(-2s+1)+9=0

We multiply parentheses

-2s^2+s+9=0

a = -2; b = 1; c = +9;
Δ = b2-4ac
Δ = 12-4·(-2)·9
Δ = 73
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-\sqrt{73}}{2*-2}=\frac{-1-\sqrt{73}}{-4}
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{73}}{2*-2}=\frac{-1+\sqrt{73}}{-4}
$