F(x)=12/x+6

Solution for F(x)=12/x+6 equation:

(F)=12/F+6

We move all terms to the left:

(F)-(12/F+6)=0


Domain of the equation: F+6)!=0

F∈R


We get rid of parentheses

F-12/F-6=0

We multiply all the terms by the denominator


F*F-6*F-12=0

We add all the numbers together, and all the variables

-6F+F*F-12=0

Wy multiply elements

F^2-6F-12=0

a = 1; b = -6; c = -12;
Δ = b2-4ac
Δ = -62-4·1·(-12)
Δ = 84
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{84}=\sqrt{4*21}=\sqrt{4}*\sqrt{21}=2\sqrt{21}$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-2\sqrt{21}}{2*1}=\frac{6-2\sqrt{21}}{2}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+2\sqrt{21}}{2*1}=\frac{6+2\sqrt{21}}{2}
$