Answer
$x^{4a+7}$
Work Step by Step
We are given the expression $x^{4a}\times x^{7}$.
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).
$x^{4a}\times x^{7}=x^{4a+7}$