Math Problem Statement

Find the domain and range and graph the function f(x)=-|2X| + 7

Solution

To find the domain and range of the function f(x)=2x+7f(x) = -|2x| + 7, let’s break it down step by step:

1. Domain:

The function involves an absolute value, but there are no restrictions like divisions by zero or square roots of negative numbers. Therefore, the domain is all real numbers, because for any value of xx, 2x|2x| is defined.

Domain: (,)\text{Domain}: \ (-\infty, \infty)

2. Range:

The function f(x)=2x+7f(x) = -|2x| + 7 is a reflection of the absolute value function 2x|2x| across the xx-axis (due to the negative sign) and then shifted up by 7.

  • The minimum value of 2x|2x| is 0 (when x=0x = 0).
  • Thus, the maximum value of f(x)f(x) occurs when x=0x = 0, giving f(0)=2(0)+7=7f(0) = -|2(0)| + 7 = 7.
  • As 2x|2x| increases as xx moves away from 0, the function 2x-|2x| will decrease, so f(x)f(x) will take values smaller than or equal to 7.

Therefore, the range is: Range:(,7]\text{Range}: (-\infty, 7]

3. Graphing:

The graph of f(x)=2x+7f(x) = -|2x| + 7 is a "V" shape, opening downward. The vertex of the graph is at (0,7)(0, 7), and since the slope of 2x-|2x| is steeper than the typical x-|x|, the "V" will be narrower than the standard absolute value function.

The key points for graphing:

  • At x=0x = 0, f(0)=7f(0) = 7.
  • For x=1x = 1, f(1)=2(1)+7=2+7=5f(1) = -|2(1)| + 7 = -2 + 7 = 5.
  • For x=1x = -1, f(1)=2(1)+7=2+7=5f(-1) = -|2(-1)| + 7 = -2 + 7 = 5.
  • As xx \to \infty or xx \to -\infty, the function approaches -\infty.

If you'd like, I can generate a graph of this function for better visualization.


Would you like a detailed graph of this function or further clarifications?

Here are 5 questions related to this:

  1. What happens to the graph if the absolute value coefficient changes?
  2. How would the graph shift if the constant was different, say f(x)=2x+10f(x) = -|2x| + 10?
  3. How does the negative sign in front of the absolute value impact the graph?
  4. How would the domain change if the function involved a square root?
  5. How can we determine the range of a function without graphing?

Tip: When dealing with absolute value functions, always check for vertex points and symmetry in the graph!

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Functions
Graphing Functions

Formulas

f(x) = -|2x| + 7

Theorems

Properties of Absolute Value
Vertex Form of Absolute Value Functions

Suitable Grade Level

Grades 9-12