Answer
$-a^{28}b^{7}$
Work Step by Step
Based on the power of a product rule, we know that $(ab)^{n}=a^{n}b^{n}$ (where $n$ is a positive integer and $a$ and $b$ are real numbers).
Based on the power rule for exponents, we know that $(a^{m})^{n}=a^{mn}$ (where $m$ and $n$ are positive integers and $a$ is a real number).
Therefore, $(-a^{4}b)^{7}=(-1)^{7}\times a^{4\times7}\times b^{7}=-a^{28}b^{7}$.
