CPM Homework Help : A2C Problem 13-88

What is the fifth term of each expansion?

$\left(a + b\right)^{9}$
Hint (a):
Use the binomial theorem.
Answer (a):
_{$\large{_{9}C_{5} · a^{5} · b^{9−5} = 126a^{5}b^{4}}$}