Use the Binomial Theorem.

Apply the product rule to .

Raise to the power of .

Apply the product rule to .

Raise to the power of .

Multiply by .

Multiply by .

Apply the product rule to .

Raise to the power of .

Multiply by .

One to any power is one.

Multiply by .

Multiply by .

One to any power is one.

Multiply by .

One to any power is one.

Expand (2x+1)^4