Math Problem Statement

What is the extreme value of f(x) = |3x + 6| - 4?

Solution

Let's break down the problem and solve it step by step. The function given is:

f(x)=3x+64f(x) = |3x + 6| - 4

Step 1: Analyze the function

The expression involves an absolute value, so we need to break it into two cases based on when 3x+63x + 6 is positive or negative.

Case 1: 3x+603x + 6 \geq 0, or x2x \geq -2

In this case, the function becomes:

f(x)=(3x+6)4=3x+2f(x) = (3x + 6) - 4 = 3x + 2

Case 2: 3x+6<03x + 6 < 0, or x<2x < -2

Here, the absolute value will flip the sign of 3x+63x + 6, and the function becomes:

f(x)=(3x+6)4=3x64=3x10f(x) = -(3x + 6) - 4 = -3x - 6 - 4 = -3x - 10

Step 2: Find where the function changes

The function changes at x=2x = -2, where 3x+6=03x + 6 = 0. This is the critical point where the absolute value changes its behavior.

Step 3: Evaluate the function at x=2x = -2

At x=2x = -2, we substitute into the original function:

f(2)=3(2)+64=04=4f(-2) = |3(-2) + 6| - 4 = |0| - 4 = -4

So, f(2)=4f(-2) = -4.

Step 4: Behavior of the function

  • For x<2x < -2, the function is f(x)=3x10f(x) = -3x - 10, which is decreasing because the slope is negative.
  • For x2x \geq -2, the function is f(x)=3x+2f(x) = 3x + 2, which is increasing because the slope is positive.

Thus, the function has a minimum at x=2x = -2.

Step 5: Conclusion

The minimum value of the function is 4-4, and it occurs at x=2x = -2.

Answer:

  • The point where an extreme value occurs is (2,4)(-2, -4).
  • It is a minimum because the function changes from decreasing to increasing.
  • This occurs when x=2x = -2.
  • The absolute minimum value of the function is -4.

Would you like more details or have any questions?

Here are 5 related questions:

  1. How do you graph absolute value functions?
  2. What are the key features of piecewise functions?
  3. How do you determine increasing and decreasing intervals of a function?
  4. Can you explain how to find the critical points of a function?
  5. What is the effect of shifting absolute value functions horizontally or vertically?

Tip: Always check the turning points of absolute value functions, as these often indicate key features like minimums or maximums.

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Functions
Piecewise Functions

Formulas

f(x) = |ax + b| - c
Solving Absolute Value Equations

Theorems

Extreme Value Theorem
Properties of Absolute Value Functions

Suitable Grade Level

Grades 9-11