P=81-0.01s^2

Solution for P=81-0.01s^2 equation:

=81-0.01P^2

We move all terms to the left:

-(81-0.01P^2)=0

We get rid of parentheses

0.01P^2-81=0

a = 0.01; b = 0; c = -81;
Δ = b2-4ac
Δ = 02-4·0.01·(-81)
Δ = 3.24
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{3.24}}{2*0.01}=\frac{0-\sqrt{3.24}}{0.02}
=-\frac{\sqrt{}}{0.02}
$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{3.24}}{2*0.01}=\frac{0+\sqrt{3.24}}{0.02}
=\frac{\sqrt{}}{0.02}
$