evaluate the limit, if it exists. (if an answer does not exist, enter dne.)\n lim_{x\rightarrow36}\frac{36…

evaluate the limit, if it exists. (if an answer does not exist, enter dne.)\n lim_{x\rightarrow36}\frac{36 - x}{6-sqrt{x}}
Answer
Explanation:
Step1: Rationalize the denominator
Multiply numerator and denominator by $6 + \sqrt{x}$: [ \begin{align*} \lim_{x\rightarrow36}\frac{36 - x}{6-\sqrt{x}}&=\lim_{x\rightarrow36}\frac{(36 - x)(6+\sqrt{x})}{(6-\sqrt{x})(6 + \sqrt{x})}\ \end{align*} ] Since $(a - b)(a + b)=a^{2}-b^{2}$, the denominator $(6-\sqrt{x})(6 + \sqrt{x})=36 - x$. So the expression becomes $\lim_{x\rightarrow36}(6+\sqrt{x})$.
Step2: Substitute $x = 36$
Substitute $x = 36$ into $6+\sqrt{x}$: $6+\sqrt{36}=6 + 6=12$
Answer:
$12$