f2+18f=0

Solution for f2+18f=0 equation:

f2+18f=0

We add all the numbers together, and all the variables

f^2+18f=0

a = 1; b = 18; c = 0;
Δ = b2-4ac
Δ = 182-4·1·0
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$f_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-18}{2*1}=\frac{-36}{2}
=-18$
$f_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+18}{2*1}=\frac{0}{2}
=0$