P=4x2-24x+20

Solution for P=4x2-24x+20 equation:

=4P^2-24P+20

We move all terms to the left:

-(4P^2-24P+20)=0

We get rid of parentheses

-4P^2+24P-20=0

a = -4; b = 24; c = -20;
Δ = b2-4ac
Δ = 242-4·(-4)·(-20)
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(24)-16}{2*-4}=\frac{-40}{-8}
=+5
$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(24)+16}{2*-4}=\frac{-8}{-8}
=1
$