Math Problem Statement

Evaluate f(x) = -2 |x - 5| at each value and simplify. f(4) and f(x^2 + 5)

Solution

Let's analyze and solve the given problems based on the image.

Problem 12: Evaluate f(x)=2x5f(x) = -2 |x - 5| at each value and simplify.

a. f(4)f(4)

You already started solving this:

  • f(4)=245f(4) = -2 |4 - 5|
  • =21= -2 |-1|
  • The absolute value of 1-1 is 11, so f(4)=2×1=2f(4) = -2 \times 1 = -2.

Thus, the value of f(4)f(4) is -2.

b. f(x2+5)f(x^2 + 5)

Here, we evaluate the same function with x2+5x^2 + 5 inside the absolute value:

  • f(x2+5)=2x2+55f(x^2 + 5) = -2 |x^2 + 5 - 5|
  • Simplifying inside the absolute value: f(x2+5)=2x2f(x^2 + 5) = -2 |x^2|
  • Since x2=x2|x^2| = x^2 (because squaring a number always gives a non-negative result), we have f(x2+5)=2x2f(x^2 + 5) = -2 x^2.

Thus, the simplified expression for f(x2+5)f(x^2 + 5) is -2x².

Would you like further clarification on any part of this?

Here are 5 questions related to this topic:

  1. What happens if we evaluate f(x)f(x) for x>5x > 5?
  2. How would the graph of f(x)=2x5f(x) = -2 |x - 5| look like?
  3. How does the value of xx affect the absolute value expression in f(x)=2x5f(x) = -2 |x - 5|?
  4. What would f(10)f(10) be, using the same function f(x)=2x5f(x) = -2 |x - 5|?
  5. How would the result differ if the coefficient outside the absolute value were positive instead of negative?

Tip: Always simplify the expression inside absolute values before applying any coefficients outside.

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Math Problem Analysis

Mathematical Concepts

Absolute Value
Functions
Simplification

Formulas

f(x) = -2 |x - 5|

Theorems

Absolute Value Properties

Suitable Grade Level

Grades 9-11