F(x)=x^2-8x-10

Solution for F(x)=x^2-8x-10 equation:

(F)=F^2-8F-10

We move all terms to the left:

(F)-(F^2-8F-10)=0

We get rid of parentheses

-F^2+F+8F+10=0

We add all the numbers together, and all the variables

-1F^2+9F+10=0

a = -1; b = 9; c = +10;
Δ = b2-4ac
Δ = 92-4·(-1)·10
Δ = 121
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{121}=11$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-11}{2*-1}=\frac{-20}{-2}
=+10
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+11}{2*-1}=\frac{2}{-2}
=-1
$