1/3x+x=84

Solution for 1/3x+x=84 equation:

1/3x+x=84

We move all terms to the left:

1/3x+x-(84)=0


Domain of the equation: 3x!=0

x!=0/3

x!=0

x∈R


We add all the numbers together, and all the variables

x+1/3x-84=0

We multiply all the terms by the denominator


x*3x-84*3x+1=0

Wy multiply elements

3x^2-252x+1=0

a = 3; b = -252; c = +1;
Δ = b2-4ac
Δ = -2522-4·3·1
Δ = 63492
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:

$\sqrt{\Delta}=\sqrt{63492}=\sqrt{4*15873}=\sqrt{4}*\sqrt{15873}=2\sqrt{15873}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-252)-2\sqrt{15873}}{2*3}=\frac{252-2\sqrt{15873}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-252)+2\sqrt{15873}}{2*3}=\frac{252+2\sqrt{15873}}{6}
$