3x^2-9x=18x^2

Solution for 3x^2-9x=18x^2 equation:

3x^2-9x=18x^2

We move all terms to the left:

3x^2-9x-(18x^2)=0

determiningTheFunctionDomain
3x^2-18x^2-9x=0

We add all the numbers together, and all the variables

-15x^2-9x=0

a = -15; b = -9; c = 0;
Δ = b2-4ac
Δ = -92-4·(-15)·0
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-9}{2*-15}=\frac{0}{-30}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+9}{2*-15}=\frac{18}{-30}
=-3/5
$