Answer
$\lim\limits_{x \to -\infty}\frac{5x^2}{x+3} = -\infty$
Work Step by Step
We look at the terms with highest degree in the numerator and denominator, as these will be the only terms with any significance when x approaches infinity.
$\lim\limits_{x \to -\infty}\frac{5x^2}{x+3} = \lim\limits_{x \to -\infty}\frac{5x^2}{x} = \lim\limits_{x \to -\infty}5x = -\infty$
