(c) Let \( f(x)=\frac{2 x+12}{x+6} \) (i) \( \lim _{x \rightarrow 6^{+}} f(x) \) (ii) \( \lim _{x \rightarrow 6^{-}} f(x) \) (iii) Use (i) and (ii) to deduce \( \lim f(x) \) at \( x=6 \).
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To evaluate the limits: (i) To compute \( \lim _{x \rightarrow 6^{+}} f(x) \): We substitute values of \( x \) approaching \( 6 \) from the right. Directly plugging in, we have: \[ f(6) = \frac{2(6) + 12}{6 + 6} = \frac{12 + 12}{12} = \frac{24}{12} = 2. \] Thus, \( \lim _{x \rightarrow 6^{+}} f(x) = 2. \) (ii) For \( \lim _{x \rightarrow 6^{-}} f(x) \): Similar to part (i), we substitute values of \( x \) approaching \( 6 \) from the left. Directly plugging in gives us: \[ f(6) = \frac{2(6) + 12}{6 + 6} = \frac{24}{12} = 2. \] Therefore, \( \lim _{x \rightarrow 6^{-}} f(x) = 2. \) (iii) Since both one-sided limits exist and are equal: \[ \lim_{x \rightarrow 6^{+}} f(x) = 2 \quad \text{and} \quad \lim_{x \rightarrow 6^{-}} f(x) = 2, \] we can conclude that: \[ \lim_{x \rightarrow 6} f(x) = 2. \]