## Intermediate Algebra (6th Edition)

$x^{15}$
We are given the expression $x^{7}\times x^{8}$. 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). $x^{7}\times x^{8}=x^{7+8}=x^{15}$