Since both terms are perfect cubes, factor using the difference of cubes formula, where and .

Simplify.

Subtract from .

Add and .

Rewrite as .

Expand using the FOIL Method.

Apply the distributive property.

Apply the distributive property.

Apply the distributive property.

Simplify and combine like terms.

Simplify each term.

Multiply by .

Multiply by .

Add and .

Reorder and .

Add and .

Apply the distributive property.

Multiply by .

Add and .

Add and .

Add and .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Move .

Simplify ((x+h)^3-x^3)/h