F(x)=9x^2-18x

Solution for F(x)=9x^2-18x equation:

(F)=9F^2-18F

We move all terms to the left:

(F)-(9F^2-18F)=0

We get rid of parentheses

-9F^2+F+18F=0

We add all the numbers together, and all the variables

-9F^2+19F=0

a = -9; b = 19; c = 0;
Δ = b2-4ac
Δ = 192-4·(-9)·0
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-19}{2*-9}=\frac{-38}{-18}
=2+1/9
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+19}{2*-9}=\frac{0}{-18}
=0
$