30x^2+40x=x

Solution for 30x^2+40x=x equation:

30x^2+40x=x

We move all terms to the left:

30x^2+40x-(x)=0

We add all the numbers together, and all the variables

30x^2+39x=0

a = 30; b = 39; c = 0;
Δ = b2-4ac
Δ = 392-4·30·0
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(39)-39}{2*30}=\frac{-78}{60}
=-1+3/10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(39)+39}{2*30}=\frac{0}{60}
=0
$