Find the 5th term of the expansion of (2x + 1)⁹. Give its coefficient and the power of x in it.

The general term is $T_{r+1} = {}^nC_r\,a^{n-r}b^r$. To find the term with a given power of $x$, write that power in terms of $r$ and set it equal to the power you want. Solve for $r$, and check that $r$ is a whole number from $0$ to $n$.