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 .

Rewrite using the commutative property of multiplication.

Multiply by .

Multiply by .

Multiply by .

Subtract from .

Move .

Subtract from .

Subtract from .

Add and .

Simplify (h-k)^2-k^2