x(x+8)(x-8)=1440

Solution for x(x+8)(x-8)=1440 equation:

x(x+8)(x-8)=1440

We move all terms to the left:

x(x+8)(x-8)-(1440)=0

We use the square of the difference formula

x^2-64-1440=0

We add all the numbers together, and all the variables

x^2-1504=0

a = 1; b = 0; c = -1504;
Δ = b2-4ac
Δ = 02-4·1·(-1504)
Δ = 6016
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:

$\sqrt{\Delta}=\sqrt{6016}=\sqrt{64*94}=\sqrt{64}*\sqrt{94}=8\sqrt{94}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8\sqrt{94}}{2*1}=\frac{0-8\sqrt{94}}{2}
=-\frac{8\sqrt{94}}{2}
=-4\sqrt{94}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8\sqrt{94}}{2*1}=\frac{0+8\sqrt{94}}{2}
=\frac{8\sqrt{94}}{2}
=4\sqrt{94}
$