Use the binomial expansion theorem to find each term. The binomial theorem states .

Expand the summation.

Simplify the exponents for each term of the expansion.

Multiply by by adding the exponents.

Multiply by .

Raise to the power of .

Use the power rule to combine exponents.

Add and .

Simplify .

One to any power is one.

Evaluate the exponent.

Multiply by .

Simplify.

Multiply by .

Multiply by by adding the exponents.

Multiply by .

Raise to the power of .

Use the power rule to combine exponents.

Add and .

Simplify .

Apply the product rule to .

Raise to the power of .

Expand using the Binomial Theorem (1-2y)^2