F(-2)=-4x^2-7x+12

Solution for F(-2)=-4x^2-7x+12 equation:

(-2)=-4F^2-7F+12

We move all terms to the left:

(-2)-(-4F^2-7F+12)=0

We add all the numbers together, and all the variables

-(-4F^2-7F+12)-2=0

We get rid of parentheses

4F^2+7F-12-2=0

We add all the numbers together, and all the variables

4F^2+7F-14=0

a = 4; b = 7; c = -14;
Δ = b2-4ac
Δ = 72-4·4·(-14)
Δ = 273
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{273}}{2*4}=\frac{-7-\sqrt{273}}{8}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+\sqrt{273}}{2*4}=\frac{-7+\sqrt{273}}{8}
$