Math Problem Statement

For the function f(x) = (3x - 13) / (x + 5), complete the following parts: (a) Find f(x) for x = -1 and q, if possible. (b) Find the domain of f.

Solution

Let's solve this step by step.

We are given the function:
f(x)=3x13x+5.f(x) = \frac{3x - 13}{x + 5}.


Part (a)

We need to find f(x)f(x) for x=1x = -1 and qq, if possible.

  1. For x=1x = -1:
    Substitute x=1x = -1 into the function:
    f(1)=3(1)13(1)+5.f(-1) = \frac{3(-1) - 13}{(-1) + 5}.
    Simplify the numerator and denominator:
    f(1)=3134=164=4.f(-1) = \frac{-3 - 13}{4} = \frac{-16}{4} = -4.
    So, f(1)=4f(-1) = -4.
    The correct choice for f(1)f(-1) is A.

  2. For qq:
    Since qq is undefined here, we cannot evaluate f(q)f(q). However, the result depends on whether q=5q = -5 (which would make the denominator zero). If q=5q = -5, then f(q)f(q) is undefined. Otherwise, we can substitute qq as done for 1-1. Without more details, the answer would likely be:

  • If q=5q = -5, the value is undefined.
  • Otherwise, f(q)f(q) can be calculated as shown above.

Part (b): Domain of f(x)f(x)

The function f(x)=3x13x+5f(x) = \frac{3x - 13}{x + 5} is undefined when the denominator equals zero:
x+5=0    x=5.x + 5 = 0 \implies x = -5.
Thus, the domain of ff is all real numbers except x=5x = -5.

The correct choice for the domain is:

  • B: "The domain is all real numbers, except for x5x \neq -5."

Final Answers:

  1. (a):

    • f(1)=4f(-1) = -4 → Choice A.
    • f(q)f(q) depends on qq; if q=5q = -5, f(q)f(q) is undefined → Likely B.
  2. (b):

    • The domain is all real numbers except x5x \neq -5 → Choice B.

Let me know if you want further clarification!

Here are 5 related questions to expand your understanding:

  1. How do you determine the domain of a rational function?
  2. What happens to the graph of a rational function at undefined points?
  3. How would you find vertical asymptotes for a function like f(x)=3x13x+5f(x) = \frac{3x - 13}{x + 5}?
  4. Can you simplify or factor the function f(x)=3x13x+5f(x) = \frac{3x - 13}{x + 5}?
  5. How do you test for holes in a rational function's graph?

Tip: Always check where the denominator equals zero when determining the domain of rational functions.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Domain of a Function

Formulas

Rational function: f(x) = (numerator) / (denominator)
Domain: denominator ≠ 0

Theorems

Undefined points in rational functions occur where the denominator is zero.

Suitable Grade Level

Grade 9-11