Factor (ab + ac + bc)^3 - a^3*b^3.
Try difference of squares.
\( (ab + ac + bc)^3 - a^3*b^3.\\ = (ab + ac + bc)^3 - (ab)^3\)
difference of 2 cubes
\(\boxed{a^3-b^3=(a-b)(a^2+ab+b^2)}\)
You can take if from there.
