-9f^2-9f-2=0

Solution for -9f^2-9f-2=0 equation:

-9f^2-9f-2=0

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

$\sqrt{\Delta}=\sqrt{9}=3$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-3}{2*-9}=\frac{6}{-18}
=-1/3
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+3}{2*-9}=\frac{12}{-18}
=-2/3
$