F(-2)=3x^2+7x-6

Solution for F(-2)=3x^2+7x-6 equation:

(-2)=3F^2+7F-6

We move all terms to the left:

(-2)-(3F^2+7F-6)=0

We add all the numbers together, and all the variables

-(3F^2+7F-6)-2=0

We get rid of parentheses

-3F^2-7F+6-2=0

We add all the numbers together, and all the variables

-3F^2-7F+4=0

a = -3; b = -7; c = +4;
Δ = b2-4ac
Δ = -72-4·(-3)·4
Δ = 97
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-\sqrt{97}}{2*-3}=\frac{7-\sqrt{97}}{-6}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{97}}{2*-3}=\frac{7+\sqrt{97}}{-6}
$