Answer
$$\lim\limits_{x\to-\infty}(x^2+2x^7)=-\infty$$
Work Step by Step
$$\lim\limits_{x\to-\infty}(x^2+2x^7)$$$$=\lim\limits_{x\to-\infty}x^7\Bigg(\frac{1}{x^5}+2\Bigg)$$$$=\lim\limits_{x\to-\infty}(x^7)\times\Bigg[\lim\limits_{x\to-\infty}\Big(\frac{1}{x^5}\Big)+2\Bigg]$$$$=-\infty\times(0+2)$$$$=-\infty$$