3s(s-2)=28

Solution for 3s(s-2)=28 equation:

3s(s-2)=28

We move all terms to the left:

3s(s-2)-(28)=0

We multiply parentheses

3s^2-6s-28=0

a = 3; b = -6; c = -28;
Δ = b2-4ac
Δ = -62-4·3·(-28)
Δ = 372
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:

$\sqrt{\Delta}=\sqrt{372}=\sqrt{4*93}=\sqrt{4}*\sqrt{93}=2\sqrt{93}$
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-2\sqrt{93}}{2*3}=\frac{6-2\sqrt{93}}{6}
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+2\sqrt{93}}{2*3}=\frac{6+2\sqrt{93}}{6}
$