f2=2.6

Solution for f2=2.6 equation:

f2=2.6

We move all terms to the left:

f2-(2.6)=0

We add all the numbers together, and all the variables

f^2-2.6=0

a = 1; b = 0; c = -2.6;
Δ = b2-4ac
Δ = 02-4·1·(-2.6)
Δ = 10.4
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{-(0)-\sqrt{10.4}}{2*1}=\frac{0-\sqrt{10.4}}{2}
=-\frac{\sqrt{}}{2}
$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{10.4}}{2*1}=\frac{0+\sqrt{10.4}}{2}
=\frac{\sqrt{}}{2}
$