Answer
If $x\to \infty$, then $y\to -\infty$
If $x\to -\infty$, then $y\to -\infty$
Work Step by Step
$$f(x)=3+2x-4x^2-5x^{10}$$
Reorder:
$$f(x)=-5x^{10}-4x^2+2x+3$$
Since degree of polynomial is even ($10$) and leading coefficient is negative ($-5$), then end behavior is:
If $x\to \infty$, then $y\to -\infty$
If $x\to -\infty$, then $y\to -\infty$