Answer
$3x$
Work Step by Step
Based on the quotient rule for exponents, we know that $\frac{a^{m}}{{a}^{n}}=a^{m-n}, a\ne0$ (where $m$ and $n$ are positive integers and $a$ is a real number).
Therefore, $\frac{3x^{5}}{x^{4}}=3\times x^{5-4}=3\times x^{1}=3x$.