a) $\displaystyle \lim_{x\to \infty} (11+x^{-4}) =$

b) $\displaystyle \lim_{x\to -\infty} \dfrac{3x^{4}+11 x^5}{2x^{8}+4} =$

c) $\displaystyle \lim_{x\to \infty} \left(\dfrac{5 x^3}{x^3+2x^2} +1\right) =$

Hint: