Math Problem Statement

f(x)=2x-9 g(x)=-x+4 f o g(x)

Solution

To find the composition of the functions ff and gg, denoted as (fg)(x)(f \circ g)(x), you need to substitute g(x)g(x) into f(x)f(x).

Given:

  • f(x)=2x9f(x) = 2x - 9
  • g(x)=x+4g(x) = -x + 4

Now, calculate (fg)(x)(f \circ g)(x): (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x)) Substitute g(x)=x+4g(x) = -x + 4 into f(x)f(x): f(g(x))=f(x+4)f(g(x)) = f(-x + 4) Now, replace xx in f(x)=2x9f(x) = 2x - 9 with x+4-x + 4: f(x+4)=2(x+4)9f(-x + 4) = 2(-x + 4) - 9 Distribute and simplify: f(x+4)=2x+89f(-x + 4) = -2x + 8 - 9 f(x+4)=2x1f(-x + 4) = -2x - 1

So, the composition (fg)(x)=2x1(f \circ g)(x) = -2x - 1.

Would you like more details or have any questions?

Here are 5 related questions:

  1. How would you find gf(x)g \circ f(x)?
  2. What is the value of (fg)(2)(f \circ g)(2)?
  3. How do you find the inverse of f(x)f(x)?
  4. What is the domain of the function fg(x)f \circ g(x)?
  5. How do you graph the function fg(x)f \circ g(x)?

Tip: When composing functions, always replace the entire variable in the outer function with the expression from the inner function.

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Math Problem Analysis

Mathematical Concepts

Functions
Composition of Functions
Linear Functions

Formulas

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Theorems

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Suitable Grade Level

High School