Math Problem Statement

find the following limit limit->-2 (x^2+8x+12)/(x+2)

Solution

To find the limit:

limx2x2+8x+12x+2\lim_{x \to -2} \frac{x^2 + 8x + 12}{x + 2}

Let's first try to substitute x=2x = -2 directly into the expression. Doing so gives:

(2)2+8(2)+122+2=416+120=00\frac{(-2)^2 + 8(-2) + 12}{-2 + 2} = \frac{4 - 16 + 12}{0} = \frac{0}{0}

This results in an indeterminate form 00\frac{0}{0}, which means we need to simplify the expression further, typically by factoring.

Step 1: Factor the numerator

We can factor the quadratic expression x2+8x+12x^2 + 8x + 12:

x2+8x+12=(x+2)(x+6)x^2 + 8x + 12 = (x + 2)(x + 6)

Step 2: Simplify the expression

Now, substitute the factored form into the limit expression:

(x+2)(x+6)x+2\frac{(x + 2)(x + 6)}{x + 2}

We can cancel out the common factor (x+2)(x + 2) in the numerator and denominator:

=x+6forx2= x + 6 \quad \text{for} \quad x \neq -2

Step 3: Take the limit

Now that the expression is simplified, we can substitute x=2x = -2:

limx2(x+6)=2+6=4\lim_{x \to -2} (x + 6) = -2 + 6 = 4

Thus, the limit is:

4\boxed{4}

Would you like more details on any step, or do you have any questions?

Here are 5 related questions for further practice:

  1. Find the limit limx3x29x3\lim_{x \to 3} \frac{x^2 - 9}{x - 3}.
  2. Determine the limit limx1x31x1\lim_{x \to 1} \frac{x^3 - 1}{x - 1}.
  3. Evaluate the limit limx0x3+3x2x\lim_{x \to 0} \frac{x^3 + 3x^2}{x}.
  4. Solve the limit limx5x225x5\lim_{x \to 5} \frac{x^2 - 25}{x - 5}.
  5. Find the limit limx1x3+1x+1\lim_{x \to -1} \frac{x^3 + 1}{x + 1}.

Tip: When you get a 00\frac{0}{0} indeterminate form, factoring or applying L'Hopital's Rule are common methods to resolve it.

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Math Problem Analysis

Mathematical Concepts

Limits
Algebra
Factoring
Indeterminate Forms

Formulas

Limit of a function as x approaches a value
Factoring quadratic equations

Theorems

Factorization
Limit properties

Suitable Grade Level

Grades 10-12