F(x)=6x^2-20

Solution for F(x)=6x^2-20 equation:

(F)=6F^2-20

We move all terms to the left:

(F)-(6F^2-20)=0

We get rid of parentheses

-6F^2+F+20=0

a = -6; b = 1; c = +20;
Δ = b2-4ac
Δ = 12-4·(-6)·20
Δ = 481
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{-(1)-\sqrt{481}}{2*-6}=\frac{-1-\sqrt{481}}{-12}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{481}}{2*-6}=\frac{-1+\sqrt{481}}{-12}
$