What is the end behavior of the graph of the polynomial function f(x) = –x^5 + 9x^4 – 18x^3?

Hello

For example, the monomial y = x 2 has the following end behavior: y → ∞ as x → −∞ and y → ∞ as x → ∞ 
For any polynomial, the end behavior is determined by the term that contains the highest power of x, because when x is large, the other terms are relatively insignificant in size.