P(x)=6.4x2-x

Solution for P(x)=6.4x2-x equation:

(P)=6.4P^2-P

We move all terms to the left:

(P)-(6.4P^2-P)=0

We get rid of parentheses

-6.4P^2+P+P=0

We add all the numbers together, and all the variables

-6.4P^2+2P=0

a = -6.4; b = 2; c = 0;
Δ = b2-4ac
Δ = 22-4·(-6.4)·0
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$P_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2}{2*-6.4}=\frac{-4}{-12.8}
=1/3.2
$
$P_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2}{2*-6.4}=\frac{0}{-12.8}
=0
$