72=-12x(-3x)

Solution for 72=-12x(-3x) equation:

72=-12x(-3x)

We move all terms to the left:

72-(-12x(-3x))=0


We calculate terms in parentheses: -(-12x(-3x)), so:

-12x(-3x)

We multiply parentheses

36x^2

Back to the equation:

-(36x^2)


a = -36; b = 0; c = +72;
Δ = b2-4ac
Δ = 02-4·(-36)·72
Δ = 10368
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:

$\sqrt{\Delta}=\sqrt{10368}=\sqrt{5184*2}=\sqrt{5184}*\sqrt{2}=72\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-72\sqrt{2}}{2*-36}=\frac{0-72\sqrt{2}}{-72}
=-\frac{72\sqrt{2}}{-72}
=-\frac{\sqrt{2}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+72\sqrt{2}}{2*-36}=\frac{0+72\sqrt{2}}{-72}
=\frac{72\sqrt{2}}{-72}
=\frac{\sqrt{2}}{-1}
$