P(x)=x(2)+40x-300

Solution for P(x)=x(2)+40x-300 equation:

(P)=P(2)+40P-300

We move all terms to the left:

(P)-(P(2)+40P-300)=0

We add all the numbers together, and all the variables

-(+P^2+40P-300)+P=0

We get rid of parentheses

-P^2-40P+P+300=0

We add all the numbers together, and all the variables

-1P^2-39P+300=0

a = -1; b = -39; c = +300;
Δ = b2-4ac
Δ = -392-4·(-1)·300
Δ = 2721
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{-(-39)-\sqrt{2721}}{2*-1}=\frac{39-\sqrt{2721}}{-2}
$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-39)+\sqrt{2721}}{2*-1}=\frac{39+\sqrt{2721}}{-2}
$