F(x)=9.0-0.4x/x

Solution for F(x)=9.0-0.4x/x equation:

(F)=9.0-0.4F/F

We move all terms to the left:

(F)-(9.0-0.4F/F)=0


Domain of the equation: F)!=0

F!=0/1

F!=0

F∈R


We add all the numbers together, and all the variables

F-(-0.4F/F+9)=0

We get rid of parentheses

F+0.4F/F-9=0

We multiply all the terms by the denominator


F*F+0.4F-9*F=0

We add all the numbers together, and all the variables

-8.6F+F*F=0

Wy multiply elements

F^2-8.6F=0

a = 1; b = -8.6; c = 0;
Δ = b2-4ac
Δ = -8.62-4·1·0
Δ = 73.96
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{-(-8.6)-\sqrt{73.96}}{2*1}=\frac{8.6-\sqrt{73.96}}{2}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8.6)+\sqrt{73.96}}{2*1}=\frac{8.6+\sqrt{73.96}}{2}
$