What is the answer to this

Answer:
see explanation
Step-by-step explanation:
A polynomial expressed in standard form begins with the term with the largest exponent of the variable then lists the remaining terms in descending order of the exponents.
given
15[tex]x^{4}[/tex] - 6x + 13x² - 1 ← [tex]x^{4}[/tex] has largest exponent, hence
15[tex]x^{4}[/tex] + 13x² - 6x - 1 ← in standard form