F(3)=-4x^2-2x+5

Solution for F(3)=-4x^2-2x+5 equation:

(3)=-4F^2-2F+5

We move all terms to the left:

(3)-(-4F^2-2F+5)=0

We get rid of parentheses

4F^2+2F-5+3=0

We add all the numbers together, and all the variables

4F^2+2F-2=0

a = 4; b = 2; c = -2;
Δ = b2-4ac
Δ = 22-4·4·(-2)
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-6}{2*4}=\frac{-8}{8}
=-1
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+6}{2*4}=\frac{4}{8}
=1/2
$