Difference of Cubes

Never done this before. I think people just remember this but here goes

A³ - B³ = (A-B)(A² +AB + B²)

Found an explanation which works for me. We have two cubes where their volumes are AxAxA and BxBxB.

You can fit the blue on inside the orange one

And now you can measure the 3 parts of the remaining area
So we start with

A³ - B³ = (A-B)A² + (A-B)AB + (A-B)B²

Which is has a factor of (A-B) so

A³ - B³ = (A-B)(A² + AB + B²)