Math Problem Statement

Graph the equation: f(x) = -2|x - 4| + 2

Solution

The equation given is:

f(x)=2x4+2f(x) = -2|x - 4| + 2

This is an absolute value function of the form f(x)=axh+kf(x) = a|x - h| + k, where:

  • a=2a = -2, which controls the vertical stretch or compression and the reflection over the x-axis.
  • h=4h = 4, which is the horizontal shift, moving the vertex to x=4x = 4.
  • k=2k = 2, which is the vertical shift, moving the vertex up by 2 units.

Key points to graph this function:

  1. Vertex: The vertex is located at (h,k)=(4,2)(h, k) = (4, 2).
  2. Slope: Since a=2a = -2, the slope of the lines is 2-2 on both sides of the vertex. On the left side (for x<4x < 4), the function will have a positive slope (rising), and on the right side (for x>4x > 4), it will have a negative slope (falling).
  3. Reflection: The negative sign in front of the 2 means the graph will open downward.

Steps for graphing:

  1. Plot the vertex at (4, 2).

  2. Plot additional points:

    • For x=3x = 3: f(3)=234+2=2(1)+2=0f(3) = -2|3 - 4| + 2 = -2(1) + 2 = 0. So the point is (3,0)(3, 0).
    • For x=5x = 5: f(5)=254+2=2(1)+2=0f(5) = -2|5 - 4| + 2 = -2(1) + 2 = 0. So the point is (5,0)(5, 0).
    • For x=2x = 2: f(2)=224+2=2(2)+2=4+2=2f(2) = -2|2 - 4| + 2 = -2(2) + 2 = -4 + 2 = -2. So the point is (2,2)(2, -2).
    • For x=6x = 6: f(6)=264+2=2(2)+2=4+2=2f(6) = -2|6 - 4| + 2 = -2(2) + 2 = -4 + 2 = -2. So the point is (6,2)(6, -2).
  3. Draw the graph: Connect the points with two straight lines that form a "V" shape, opening downward, centered at the vertex (4,2)(4, 2).

Would you like more details on this graph, or do you have any questions?

Related questions:

  1. How does changing the value of aa affect the shape of the absolute value graph?
  2. What happens if we change the value of hh in the equation f(x)=2xh+2f(x) = -2|x - h| + 2?
  3. How would the graph change if the constant kk were increased or decreased?
  4. How can we find the x-intercepts of the graph?
  5. What does the reflection of the graph tell us about the function's behavior?

Tip:

When graphing absolute value functions, always locate the vertex first, and then use the slope to plot points symmetrically on both sides of the vertex.

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Functions
Graphing Functions

Formulas

f(x) = a|x - h| + k, where a is the vertical stretch/compression, h is the horizontal shift, and k is the vertical shift

Theorems

Properties of absolute value functions: symmetry and vertex at (h, k)

Suitable Grade Level

Grades 8-10