x*(15/100)=12000

Solution for x*(15/100)=12000 equation:

x(15/100)=12000

We move all terms to the left:

x(15/100)-(12000)=0

We add all the numbers together, and all the variables

x(+15/100)-12000=0

We multiply parentheses

15x^2-12000=0

a = 15; b = 0; c = -12000;
Δ = b2-4ac
Δ = 02-4·15·(-12000)
Δ = 720000
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:

$\sqrt{\Delta}=\sqrt{720000}=\sqrt{360000*2}=\sqrt{360000}*\sqrt{2}=600\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-600\sqrt{2}}{2*15}=\frac{0-600\sqrt{2}}{30}
=-\frac{600\sqrt{2}}{30}
=-20\sqrt{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+600\sqrt{2}}{2*15}=\frac{0+600\sqrt{2}}{30}
=\frac{600\sqrt{2}}{30}
=20\sqrt{2}
$