\[ \begin{split} &\lim_{x \to -1} \frac{x^4+3x^2-4}{x+1}=\\[16pt] &=\lim_{x \to -1}\frac{(x^2+4)(x^2-1)}{x+1}=\\[16pt] &=\lim_{x \to -1}\frac{(x^2+4)(x-1)(x+1)}{x+1}=\\[16pt] &=\lim_{x \to -1}(x^2+4)(x-1)=\\[16pt] &=5\cdot (-2)=-10 \end{split} \]