P(x)=-0.9x^2-2.7x+25.2

Solution for P(x)=-0.9x^2-2.7x+25.2 equation:

(P)=-0.9P^2-2.7P+25.2

We move all terms to the left:

(P)-(-0.9P^2-2.7P+25.2)=0

We get rid of parentheses

0.9P^2+2.7P+P-25.2=0

We add all the numbers together, and all the variables

0.9P^2+3.7P-25.2=0

a = 0.9; b = 3.7; c = -25.2;
Δ = b2-4ac
Δ = 3.72-4·0.9·(-25.2)
Δ = 104.41
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{-(3.7)-\sqrt{104.41}}{2*0.9}=\frac{-3.7-\sqrt{104.41}}{1.8}
$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3.7)+\sqrt{104.41}}{2*0.9}=\frac{-3.7+\sqrt{104.41}}{1.8}
$