we have
[tex] f(x) = x^{5} -9x^{3} [/tex]
using a graph tool
see the attached figure
in the graph observe that
As x goes to negative infinity-------> f(x) decreases
and
As x goes to positive infinity-------> f(x) increases
therefore
the answer is
As x goes to negative infinity, f(x) goes to negative infinity, and as x goes to positive infinity, f(x) goes to positive infinity.
