3/5x+21=x

Solution for 3/5x+21=x equation:

3/5x+21=x

We move all terms to the left:

3/5x+21-(x)=0


Domain of the equation: 5x!=0

x!=0/5

x!=0

x∈R


We add all the numbers together, and all the variables

-1x+3/5x+21=0

We multiply all the terms by the denominator


-1x*5x+21*5x+3=0

Wy multiply elements

-5x^2+105x+3=0

a = -5; b = 105; c = +3;
Δ = b2-4ac
Δ = 1052-4·(-5)·3
Δ = 11085
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(105)-\sqrt{11085}}{2*-5}=\frac{-105-\sqrt{11085}}{-10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(105)+\sqrt{11085}}{2*-5}=\frac{-105+\sqrt{11085}}{-10}
$