13s=30-s^2

Solution for 13s=30-s^2 equation:

13s=30-s^2

We move all terms to the left:

13s-(30-s^2)=0

We get rid of parentheses

s^2+13s-30=0

a = 1; b = 13; c = -30;
Δ = b2-4ac
Δ = 132-4·1·(-30)
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-17}{2*1}=\frac{-30}{2}
=-15
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+17}{2*1}=\frac{4}{2}
=2
$