Evalute $\lim_{x\to-\infty} \sqrt{x^2+4x^4}/(8+x^2)$

Evalute $\lim_{x\to-\infty} \sqrt{x^2+4x^4}/(8+x^2)$

Having a hard time with this. So far I have:
$$ \frac{\sqrt{x^2(1+4x^2)}}{8+x^2} = \frac{x\sqrt{1+4x^2}}{8+x^2}$$