F(-1)=-2x^2+5x-4

Solution for F(-1)=-2x^2+5x-4 equation:

(-1)=-2F^2+5F-4

We move all terms to the left:

(-1)-(-2F^2+5F-4)=0

We add all the numbers together, and all the variables

-(-2F^2+5F-4)-1=0

We get rid of parentheses

2F^2-5F+4-1=0

We add all the numbers together, and all the variables

2F^2-5F+3=0

a = 2; b = -5; c = +3;
Δ = b2-4ac
Δ = -52-4·2·3
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-1}{2*2}=\frac{4}{4}
=1
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+1}{2*2}=\frac{6}{4}
=1+1/2
$