F(x)=-x2-5x+36

Solution for F(x)=-x2-5x+36 equation:

(F)=-F2-5F+36

We move all terms to the left:

(F)-(-F2-5F+36)=0

We add all the numbers together, and all the variables

-(-1F^2-5F+36)+F=0

We get rid of parentheses

1F^2+5F+F-36=0

We add all the numbers together, and all the variables

F^2+6F-36=0

a = 1; b = 6; c = -36;
Δ = b2-4ac
Δ = 62-4·1·(-36)
Δ = 180
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{180}=\sqrt{36*5}=\sqrt{36}*\sqrt{5}=6\sqrt{5}$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-6\sqrt{5}}{2*1}=\frac{-6-6\sqrt{5}}{2}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+6\sqrt{5}}{2*1}=\frac{-6+6\sqrt{5}}{2}
$