F(x)=-x^2-6x+7

Solution for F(x)=-x^2-6x+7 equation:

(F)=-F^2-6F+7

We move all terms to the left:

(F)-(-F^2-6F+7)=0

We get rid of parentheses

F^2+6F+F-7=0

We add all the numbers together, and all the variables

F^2+7F-7=0

a = 1; b = 7; c = -7;
Δ = b2-4ac
Δ = 72-4·1·(-7)
Δ = 77
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{77}}{2*1}=\frac{-7-\sqrt{77}}{2}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+\sqrt{77}}{2*1}=\frac{-7+\sqrt{77}}{2}
$