Simplify: (x2+x)(x2−x)(x^2 + x)(x^2 - x)(x2+x)(x2−x).
x4−x2x^4 - x^2x4−x2
x4+x2x^4 + x^2x4+x2
x4−x4x^4 - x^4x4−x4
x3−xx^3 - xx3−x