2x(x-15)=-12

Solution for 2x(x-15)=-12 equation:

2x(x-15)=-12

We move all terms to the left:

2x(x-15)-(-12)=0

We add all the numbers together, and all the variables

2x(x-15)+12=0

We multiply parentheses

2x^2-30x+12=0

a = 2; b = -30; c = +12;
Δ = b2-4ac
Δ = -302-4·2·12
Δ = 804
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:

$\sqrt{\Delta}=\sqrt{804}=\sqrt{4*201}=\sqrt{4}*\sqrt{201}=2\sqrt{201}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-2\sqrt{201}}{2*2}=\frac{30-2\sqrt{201}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+2\sqrt{201}}{2*2}=\frac{30+2\sqrt{201}}{4}
$