27f^2+26f-1=0

Solution for 27f^2+26f-1=0 equation:

27f^2+26f-1=0

a = 27; b = 26; c = -1;
Δ = b2-4ac
Δ = 262-4·27·(-1)
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(26)-28}{2*27}=\frac{-54}{54}
=-1
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(26)+28}{2*27}=\frac{2}{54}
=1/27
$