21/5x=5+2x

Solution for 21/5x=5+2x equation:

21/5x=5+2x

We move all terms to the left:

21/5x-(5+2x)=0


Domain of the equation: 5x!=0

x!=0/5

x!=0

x∈R


We add all the numbers together, and all the variables

21/5x-(2x+5)=0

We get rid of parentheses

21/5x-2x-5=0

We multiply all the terms by the denominator


-2x*5x-5*5x+21=0

Wy multiply elements

-10x^2-25x+21=0

a = -10; b = -25; c = +21;
Δ = b2-4ac
Δ = -252-4·(-10)·21
Δ = 1465
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{-(-25)-\sqrt{1465}}{2*-10}=\frac{25-\sqrt{1465}}{-20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+\sqrt{1465}}{2*-10}=\frac{25+\sqrt{1465}}{-20}
$