When evaluating

MATHEMATICS · Single correct · AP · Calculus AB · Limits and Continuity · Limits and Continuity

Problem

When evaluating

\displaystyle\lim_{x\to 9}\dfrac{\sqrt{x}-3}{x-9}

, a student wants to rewrite the fraction so that the denominator no longer equals zero at

x=9

. Which of the following factors, when multiplied to both numerator and denominator, most directly accomplishes this goal? (a)

x-9

(b)

\sqrt{x}-3

(c)

\sqrt{x}+3

(d)

x+9