Question:
Write the number of terms in the expansion of $\left(1-3 x+3 x^{2}-x^{3}\right)^{8}$.
Solution:
The given expression is $\left(1-3 x+3 x^{2}-x^{3}\right)^{8}$. It can be written as $\left[(1-x)^{3}\right]^{8}$ i. e. $(1-x)^{24}$
Hence, the number of terms is $(24+1)$ i.e. 25