P(x)=81x^2-196

Solution for P(x)=81x^2-196 equation:

(P)=81P^2-196

We move all terms to the left:

(P)-(81P^2-196)=0

We get rid of parentheses

-81P^2+P+196=0

a = -81; b = 1; c = +196;
Δ = b2-4ac
Δ = 12-4·(-81)·196
Δ = 63505
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{-(1)-\sqrt{63505}}{2*-81}=\frac{-1-\sqrt{63505}}{-162}
$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{63505}}{2*-81}=\frac{-1+\sqrt{63505}}{-162}
$