Math Problem Statement

What is the domain and range of the absolute value function f(x) = |x| + 4?

Solution

To determine the domain and range of the function f(x)=x+4f(x) = |x| + 4, let's analyze it:

  1. Domain: The absolute value function x|x| is defined for all real values of xx. Adding 4 does not restrict the values of xx, so the domain is all real numbers.

  2. Range: The function f(x)=x+4f(x) = |x| + 4 takes the absolute value of xx and adds 4. Since x0|x| \geq 0, the smallest value of f(x)f(x) is when x=0x = 0, giving f(0)=0+4=4f(0) = 0 + 4 = 4. Therefore, f(x)4f(x) \geq 4, so the range is y4y \geq 4.

Now, let’s match these with the options provided:

  • Option (a): Domain is all real numbers, Range y4y \leq 4 – Incorrect (Range should be y4y \geq 4)
  • Option (b): Domain is all real numbers, Range y4y \geq 4 – Correct
  • Option (c): Domain is all real numbers, Range y<4y < 4 – Incorrect (Range should include values equal to and greater than 4)
  • Option (d): Domain x4x \geq 4, Range is all real numbers – Incorrect (Domain is all real numbers, not restricted to x4x \geq 4)

Correct Answer: Option (b) – Domain: all real numbers, Range: y4y \geq 4.

Would you like further details or have questions about this solution?

Here are some related questions to explore further:

  1. What is the impact on the range if we modify the function to f(x)=x4f(x) = |x| - 4?
  2. How would the graph look if we used f(x)=x+4f(x) = -|x| + 4?
  3. How do we determine the domain and range for functions involving square roots?
  4. What happens to the range if we add or subtract a constant from an absolute value function?
  5. How can transformations affect the graph of absolute value functions?

Tip: For absolute value functions of the form f(x)=x+cf(x) = |x| + c, the range starts at cc (if c0c \geq 0) and extends to infinity.

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Functions
Domain and Range

Formulas

f(x) = |x| + 4

Theorems

Properties of Absolute Value Functions

Suitable Grade Level

Grades 9-10