x-40=1/3x

Solution for x-40=1/3x equation:

x-40=1/3x

We move all terms to the left:

x-40-(1/3x)=0


Domain of the equation: 3x)!=0

x!=0/1

x!=0

x∈R


We add all the numbers together, and all the variables

x-(+1/3x)-40=0

We get rid of parentheses

x-1/3x-40=0

We multiply all the terms by the denominator


x*3x-40*3x-1=0

Wy multiply elements

3x^2-120x-1=0

a = 3; b = -120; c = -1;
Δ = b2-4ac
Δ = -1202-4·3·(-1)
Δ = 14412
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{14412}=\sqrt{4*3603}=\sqrt{4}*\sqrt{3603}=2\sqrt{3603}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-120)-2\sqrt{3603}}{2*3}=\frac{120-2\sqrt{3603}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-120)+2\sqrt{3603}}{2*3}=\frac{120+2\sqrt{3603}}{6}
$