Math Problem Statement

The functions f(x) = (x + 6) / (x^2 + 2x - 24) and g(x) = x / (x^2 + 9) are defined. Find the domain of each function and write each answer as an interval or union of intervals.

Solution

Let's break down the domain finding process for each function.

  1. Function f(x)=x+6x2+2x24f(x) = \frac{x+6}{x^2 + 2x - 24}:

    • The domain of a rational function excludes values of xx that make the denominator equal to zero.
    • Set the denominator equal to zero and solve for xx: x2+2x24=0x^2 + 2x - 24 = 0
    • Factor the quadratic equation: (x+6)(x4)=0(x + 6)(x - 4) = 0
    • So, x=6x = -6 and x=4x = 4 are the values that make the denominator zero.
    • Therefore, the domain of f(x)f(x) excludes x=6x = -6 and x=4x = 4.
    • The domain is: (,6)(6,4)(4,)(-\infty, -6) \cup (-6, 4) \cup (4, \infty)
  2. Function g(x)=xx2+9g(x) = \frac{x}{x^2 + 9}:

    • Again, the domain excludes values of xx that make the denominator zero.
    • Set the denominator equal to zero: x2+9=0x^2 + 9 = 0
    • Solving for xx, we get: x2=9x^2 = -9
    • This has no real solution because a square cannot be negative.
    • Therefore, the denominator never equals zero for real numbers, meaning the function is defined for all real numbers.
    • The domain is: (,)(-\infty, \infty)

Would you like more details or further clarification?

Here are 5 related questions:

  1. How do we handle undefined points in rational functions?
  2. Can you explain how to factor quadratic expressions like x2+2x24x^2 + 2x - 24?
  3. What happens

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Domain of a Function
Quadratic Equations

Formulas

The domain of a rational function is where the denominator is not equal to zero
Factoring quadratics: ax^2 + bx + c = 0

Theorems

Fundamental Theorem of Algebra

Suitable Grade Level

Grades 9-12