Consider the rational function f ( x ) = 7 x + 19 2 x 12 . What monomial expression best estimates the behavior of 7 x + 19 as x ? What monomial expression best estimates the behavior of 2 x 12 as x ? Using your results from parts (a) and (b), write a ratio of monomial expressions that best estimates the behavior of 7 x + 19 2 x 12 as x . Simplify your answer as much as possible. Based on your answer to part (c), what happens to the value of f ( x ) as x ? (Hint: Now your answer should be a number, , , or "DNE".) As x , f ( x ) Based on your answer to part (d), what is the horizontal asymptote of f ? (If no horizontal asymptote exists for f , enter "DNE".) y =