Math Problem Statement

Given f(x) = 2x + 5 and g(x) = -3x - 1, find g(f(x))^{-1}.

Solution

The problem presented in the image involves two functions, f(x)=2x+5f(x) = 2x + 5 and g(x)=3x1g(x) = -3x - 1, and asks for g(f(x))1g(f(x))^{-1}.

Let's break it down and solve it step by step.

Step 1: Compute g(f(x))g(f(x))

First, we substitute f(x)f(x) into g(x)g(x). This means replacing xx in g(x)g(x) with f(x)f(x).

Given:

  • f(x)=2x+5f(x) = 2x + 5
  • g(x)=3x1g(x) = -3x - 1

We substitute f(x)f(x) into g(x)g(x): g(f(x))=3(2x+5)1g(f(x)) = -3(2x + 5) - 1 Distribute the 3-3 across the terms inside the parentheses: g(f(x))=6x151g(f(x)) = -6x - 15 - 1 g(f(x))=6x16g(f(x)) = -6x - 16

Step 2: Find the inverse of g(f(x))g(f(x))

To find g(f(x))1g(f(x))^{-1}, we are looking for the inverse function. Let y=g(f(x))=6x16y = g(f(x)) = -6x - 16, and solve for xx in terms of yy.

Starting with: y=6x16y = -6x - 16 Solve for xx: y+16=6xy + 16 = -6x x=(y+16)6x = \frac{-(y + 16)}{6} Thus, the inverse function is: g(f(x))1=(y+16)6g(f(x))^{-1} = \frac{-(y + 16)}{6}

Let me know if you'd like further details on this solution or need additional explanations.

Here are five related questions:

  1. How do we generally compute the composition of functions g(f(x))g(f(x))?
  2. What are the key steps to finding the inverse of a linear function?
  3. Can the inverse process be applied to quadratic or other non-linear functions?
  4. How does the chain rule apply when differentiating a composition of functions like g(f(x))g(f(x))?
  5. What is the domain and range of g(f(x))g(f(x)) and its inverse?

Tip: When finding the inverse of a function, always ensure that the function is one-to-one (injective), as only such functions have inverses.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Inverse Functions
Linear Equations

Formulas

g(f(x)) = g(2x + 5) = -3(2x + 5) - 1 = -6x - 16
Inverse of a linear equation: y = ax + b, solve for x.

Theorems

Composition of functions
Inverse function theorem for linear equations

Suitable Grade Level

Grades 10-12