Math Problem Statement

In Exercises 9-16, find the domain of the function algebraically and support your answer graphically.

Solution

I see that you've uploaded an image containing several exercises related to finding the domain of functions algebraically and supporting the answer graphically. Let's go through the steps to find the domain for each of the functions in Exercises 9-16.

Exercises 9-16: Finding the Domain Algebraically

9. f(x)=x2+4f(x) = -x^2 + 4

  • Domain: The function f(x)=x2+4f(x) = -x^2 + 4 is a quadratic function, which is defined for all real numbers.
  • Answer: Domain = (,)(-\infty, \infty)

10. h(x)=5x3h(x) = \frac{5}{x - 3}

  • Domain: This is a rational function. The function is undefined where the denominator is zero. So, set x3=0x - 3 = 0, which gives x=3x = 3. Exclude this value from the domain.
  • Answer: Domain = (,3)(3,)(-\infty, 3) \cup (3, \infty)

11. f(x)=3x1(x+3)(x1)f(x) = \frac{3x - 1}{(x + 3)(x - 1)}

  • Domain: The function is undefined where the denominator is zero. Set (x+3)(x1)=0(x + 3)(x - 1) = 0, so x=3x = -3 and x=1x = 1. Exclude these values.
  • Answer: Domain = (,3)(3,1)(1,)(-\infty, -3) \cup (-3, 1) \cup (1, \infty)

12. h(x)=5+xx3h(x) = \frac{5 + x}{x - 3}

  • Domain: This is another rational function. Set the denominator x3=0x - 3 = 0, which gives x=3x = 3. Exclude this value.
  • Answer: Domain = (,3)(3,)(-\infty, 3) \cup (3, \infty)

13. f(x)=1x24xf(x) = \frac{1}{x^2 - 4x}

  • Domain: The denominator is x24x=0x^2 - 4x = 0. Factoring gives x(x4)=0x(x - 4) = 0, so x=0x = 0 and x=4x = 4. Exclude these values.
  • Answer: Domain = (,0)(0,4)(4,)(-\infty, 0) \cup (0, 4) \cup (4, \infty)

14. h(x)=x3x1h(x) = \frac{\sqrt{x - 3}}{x - 1}

  • Domain: The square root requires that x30x - 3 \geq 0, which gives x3x \geq 3. Also, the denominator x10x - 1 \neq 0, so x1x \neq 1. Thus, the domain is x3x \geq 3, but exclude x=1x = 1 if within that range.
  • Answer: Domain = [3,)[3, \infty), excluding x=1x = 1.

15. k(x)=x25xx1k(x) = \frac{\sqrt{x^2 - 5x}}{x - 1}

  • Domain: The square root requires x25x0x^2 - 5x \geq 0, and the denominator x10x - 1 \neq 0. First, solve the inequality for x25x0x^2 - 5x \geq 0. After factoring x(x5)0x(x - 5) \geq 0, the solution is x0x \leq 0 or x5x \geq 5. Also, exclude x=1x = 1.
  • Answer: Domain = (,0][5,)(-\infty, 0] \cup [5, \infty), excluding x=1x = 1.

16. f(x)=x216xf(x) = \sqrt{x^2 - 16x}

  • Domain: The square root requires that the expression inside the square root be non-negative: x216x0x^2 - 16x \geq 0. Factor to get x(x16)0x(x - 16) \geq 0. Solve this inequality to get x0x \leq 0 or x16x \geq 16.
  • Answer: Domain = (,0][16,)(-\infty, 0] \cup [16, \infty)

Would you like more detailed explanations for any of these problems or assistance with graphing the domains?

Here are five related questions:

  1. How do you solve inequalities involving square roots and rational expressions?
  2. What graphical techniques can help visualize the domain of rational functions?
  3. How do you factor quadratic expressions to find restrictions on the domain?
  4. What is the significance of excluding specific points from the domain of a function?
  5. How does the concept of domain change for composite functions?

Tip: Always check for domain restrictions by analyzing the denominator, square roots, and logarithmic expressions. These often define boundaries for the allowable values of xx.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Quadratic Equations
Square Roots
Inequalities

Formulas

Quadratic formula: ax^2 + bx + c = 0
Rational function domain restrictions: f(x) = P(x)/Q(x), Q(x) ≠ 0
Square root domain restrictions: √f(x) is defined when f(x) ≥ 0

Theorems

Quadratic formula
Properties of rational functions
Square root domain theorem

Suitable Grade Level

Grades 9-11