F(x)=-3x2-30x-80

Solution for F(x)=-3x2-30x-80 equation:

(F)=-3F^2-30F-80

We move all terms to the left:

(F)-(-3F^2-30F-80)=0

We get rid of parentheses

3F^2+30F+F+80=0

We add all the numbers together, and all the variables

3F^2+31F+80=0

a = 3; b = 31; c = +80;
Δ = b2-4ac
Δ = 312-4·3·80
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{-(31)-1}{2*3}=\frac{-32}{6}
=-5+1/3
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(31)+1}{2*3}=\frac{-30}{6}
=-5
$