1. The problem is to find the size or leading term of the polynomial function $$x^5 + x^3 - x + 5$$. 2. The leading term of a polynomial is the term with the highest power of $x$. 3. In the polynomial $$x^5 + x^3 - x + 5$$, the term with the highest power is $$x^5$$. 4. Therefore, the leading term is $$x^5$$, and the size of the function is dominated by this term for large values of $x$. 5. This means as $x$ becomes very large or very small, the behavior of the function is mainly influenced by $$x^5$$.