F(-2)=5x^2-7x-2

Solution for F(-2)=5x^2-7x-2 equation:

(-2)=5F^2-7F-2

We move all terms to the left:

(-2)-(5F^2-7F-2)=0

We add all the numbers together, and all the variables

-(5F^2-7F-2)-2=0

We get rid of parentheses

-5F^2+7F+2-2=0

We add all the numbers together, and all the variables

-5F^2+7F=0

a = -5; b = 7; c = 0;
Δ = b2-4ac
Δ = 72-4·(-5)·0
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-7}{2*-5}=\frac{-14}{-10}
=1+2/5
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+7}{2*-5}=\frac{0}{-10}
=0
$