\begin{array}{c}\color{#003366}{-Gw}\color{#005A9C}{en}\color{#007ACC}{St}\color{#00AEEF}{ac}\color{#00CFFF}{y}\color{#A4D3EE}{-}\color{#D3D3D3}{}\color{#E0E0E0}{}\end{array} 

`(x+1)^3 - (x-1)^3 - 6(x+1)(x-1)`

`= x^3 + 3x^2 + 3x + 1 - x^3 - 3x + 3x^2 - 6x^2 + 7`

`= x^3 - x^3 + 3x^2 + 3x^2 - 6x^2 + 3x - 3x + 1 + 7`

`= (x^3 - x^3) + (3x^2 + 3x^2 - 6x^2) + (3x - 3x) + 1 + 7`

`= 8`