72=x*(x*4)

Solution for 72=x*(x*4) equation:

72=x*(x*4)

We move all terms to the left:

72-(x*(x*4))=0

We add all the numbers together, and all the variables

-(x*(+x*4))+72=0


We calculate terms in parentheses: -(x*(+x*4)), so:

x*(+x*4)

We multiply parentheses

4x^2

Back to the equation:

-(4x^2)


a = -4; b = 0; c = +72;
Δ = b2-4ac
Δ = 02-4·(-4)·72
Δ = 1152
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:

$\sqrt{\Delta}=\sqrt{1152}=\sqrt{576*2}=\sqrt{576}*\sqrt{2}=24\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-24\sqrt{2}}{2*-4}=\frac{0-24\sqrt{2}}{-8}
=-\frac{24\sqrt{2}}{-8}
=-\frac{3\sqrt{2}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+24\sqrt{2}}{2*-4}=\frac{0+24\sqrt{2}}{-8}
=\frac{24\sqrt{2}}{-8}
=\frac{3\sqrt{2}}{-1}
$