1. [tex]\lim_{x\to+-\infty}x^3-4x^2+x\\(+-\infty)^3-4(+-\infty)^2+(+-\infty)\\\infty,-\infty[/tex]
2. [tex] \lim_{x \to +-\infty} x^4-4x^3+2x+8\\(+-\infty)^4-4(+-\infty)^3+2(+-\infty)+8\\\infty[/tex]
3. [tex] \lim_{x \to +-\infty} -2x^3-4x^2+9\\-2(+-\infty)^3-4(+-\infty)^2+9\\-\infty,\infty[/tex]
4. [tex] \lim_{x \to +-\infty} -x^4+9x^3+x^2+8x+2\\-(+-\infty)^4+9(+-\infty)^3+(+-\infty)^2+8(+-\infty)+2\\-\infty[/tex]
4 is the only function that decreases as it approaches both infinities.
