9=9+4/x-x

Solution for 9=9+4/x-x equation:

9=9+4/x-x

We move all terms to the left:

9-(9+4/x-x)=0


Domain of the equation: x-x)!=0

x∈R


We add all the numbers together, and all the variables

-(-1x+4/x+9)+9=0

We get rid of parentheses

1x-4/x-9+9=0

We multiply all the terms by the denominator


1x*x-9*x+9*x-4=0

We add all the numbers together, and all the variables

1x*x-4=0

Wy multiply elements

x^2-4=0

a = 1; b = 0; c = -4;
Δ = b2-4ac
Δ = 02-4·1·(-4)
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4}{2*1}=\frac{-4}{2}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4}{2*1}=\frac{4}{2}
=2
$