Answer
$x^{9}$
Work Step by Step
We are given the expression $x^{4}\times x^{5}$.
We can use the product rule to simplify, which holds that $a^{m}\times a^{n}=a^{m+n}$ (where a is a real number, and m and n are positive integers).
$x^{4}\times x^{5}=x^{4+5}=x^{9}$
