You can factor an 8x out of each term.
8x^3 - 8x
Factor the 8x out and put it in front of brackets:
8x( )
Now divide each term by the 8x.
8x(8x^3 / 8x - 8x/8x)
This leaves you with:
8x(x^2 - 1).
x^2 -1 is the difference between two perfect squares which factors out like this:
8x(x -1)(x+1)
To check your work, multiply the binomials using FOIL method then distribute the 8x back through the binomial and you should end up with your original problem.