2/7x+1/3x=13

Solution for 2/7x+1/3x=13 equation:

2/7x+1/3x=13

We move all terms to the left:

2/7x+1/3x-(13)=0


Domain of the equation: 7x!=0

x!=0/7

x!=0

x∈R



Domain of the equation: 3x!=0

x!=0/3

x!=0

x∈R


We calculate fractions


6x/21x^2+7x/21x^2-13=0

We multiply all the terms by the denominator


6x+7x-13*21x^2=0

We add all the numbers together, and all the variables

13x-13*21x^2=0

Wy multiply elements

-273x^2+13x=0

a = -273; b = 13; c = 0;
Δ = b2-4ac
Δ = 132-4·(-273)·0
Δ = 169
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{169}=13$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-13}{2*-273}=\frac{-26}{-546}
=1/21
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+13}{2*-273}=\frac{0}{-546}
=0
$