Math Problem Statement

Determine the limit shown below in simplest form: lim (x→7) [(-2x - 2) / (x^2 - 1)]

Solution

To solve the given limit:

limx72x2x21\lim_{x \to 7} \frac{-2x - 2}{x^2 - 1}

Step 1: Substitution

Substituting x=7x = 7 directly:

Numerator: 2(7)2=142=16\text{Numerator: } -2(7) - 2 = -14 - 2 = -16 Denominator: 721=491=48\text{Denominator: } 7^2 - 1 = 49 - 1 = 48

Thus, the limit is:

1648=13\frac{-16}{48} = \frac{-1}{3}

Final Answer:

limx72x2x21=13\lim_{x \to 7} \frac{-2x - 2}{x^2 - 1} = \boxed{-\frac{1}{3}}

Let me know if you want details about this solution!


Here are 5 relative questions to expand your understanding:

  1. What happens if the numerator or denominator becomes 00 when evaluating a limit?
  2. How do you handle indeterminate forms such as 00\frac{0}{0}?
  3. How can limits be solved using factoring or simplification?
  4. How does substitution work in evaluating limits of rational functions?
  5. Can L'Hôpital's Rule be applied to this problem? Why or why not?

Tip: Always check if substitution works first when solving limits—it’s the simplest method.

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Math Problem Analysis

Mathematical Concepts

Limits
Rational Functions
Substitution in Limits

Formulas

Direct substitution in limits

Theorems

Limit Laws

Suitable Grade Level

Grades 10-12