Math Problem Statement

Let f be the function given by f(x) = (3x^2 - 5x - 2) / (x^2 + 2x - 8). For what values of x does f have a non-removable discontinuity?

Solution

Let's analyze the problem.

The given function is:

f(x)=3x25x2x2+2x8f(x) = \frac{3x^2 - 5x - 2}{x^2 + 2x - 8}

Step 1: Factor both the numerator and the denominator

We begin by factoring the denominator and numerator to check for discontinuities.

Denominator:

x2+2x8=(x2)(x+4)x^2 + 2x - 8 = (x - 2)(x + 4) This gives two potential discontinuities at x=2x = 2 and x=4x = -4.

Numerator:

3x25x2=(3x+1)(x2)3x^2 - 5x - 2 = (3x + 1)(x - 2) The factor (x2)(x - 2) appears in both the numerator and denominator.

Step 2: Simplifying the function

The common factor of (x2)(x - 2) in both the numerator and denominator cancels out, but it still indicates a removable discontinuity at x=2x = 2.

After canceling (x2)(x - 2), the simplified function becomes:

f(x)=3x+1x+4f(x) = \frac{3x + 1}{x + 4}

Step 3: Non-removable discontinuities

The remaining denominator x+4x + 4 shows that x=4x = -4 is a non-removable discontinuity because it causes the denominator to be zero, which makes the function undefined at that point.

Conclusion:

  • At x=2x = 2, there is a removable discontinuity.
  • At x=4x = -4, there is a non-removable discontinuity.

Thus, the correct answer is (B) 4-4 only, which matches the boxed answer in the image.

Would you like more details or have any questions about this solution?

Here are 5 related questions to explore:

  1. What is the difference between removable and non-removable discontinuities?
  2. How does canceling a factor affect the type of discontinuity?
  3. Can a function have more than one removable discontinuity?
  4. What are some examples of functions with both types of discontinuities?
  5. How do you determine if a discontinuity is removable or non-removable from a graph?

Tip: Always factor both the numerator and denominator of a rational function to identify potential discontinuities.

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Discontinuities
Factoring

Formulas

f(x) = (3x^2 - 5x - 2) / (x^2 + 2x - 8)
Factoring Quadratics

Theorems

Non-Removable Discontinuity Theorem
Removable Discontinuity (Hole) in Rational Functions

Suitable Grade Level

Grade 10-12