Answer
$$a^8+8a^7b^2+28a^6b^4+56a^5b^6+70a^4b^8+56a^3b^{10}+28a^2b^{12}+8ab^{14}+b^{16}$$
Work Step by Step
We know from the Binomial Theorem (page 693) that we can expand the given expression using Pascal's Triangle. Doing this, we obtain:
$$a^8+8a^7b^2+28a^6b^4+56a^5b^6+70a^4b^8+56a^3b^{10}+28a^2b^{12}+8ab^{14}+b^{16}$$