Math Problem Statement

Given the function f(x) = (2 - 3x) / (4x + 1), find the inverse f^(-1)(x - 2).

Solution

Let's analyze the mathematical problem in the uploaded image. The question states:

The function f(x)=23x4x+1f(x) = \frac{2 - 3x}{4x + 1} is given. If f1f^{-1} is the inverse of the function f(x)f(x), find f1(x2)f^{-1}(x - 2).


Solution:

  1. Find the inverse of f(x)f(x): For y=23x4x+1y = \frac{2 - 3x}{4x + 1}, swap xx and yy: x=23y4y+1.x = \frac{2 - 3y}{4y + 1}. Solve for yy (the inverse function): Multiply through by 4y+14y + 1: x(4y+1)=23y.x(4y + 1) = 2 - 3y. Expand: 4xy+x=23y.4xy + x = 2 - 3y. Rearrange terms to isolate yy: 4xy+3y=2x.4xy + 3y = 2 - x. Factor yy on the left: y(4x+3)=2x.y(4x + 3) = 2 - x. Solve for yy: y=2x4x+3.y = \frac{2 - x}{4x + 3}. Thus, the inverse function is: f1(x)=2x4x+3.f^{-1}(x) = \frac{2 - x}{4x + 3}.

  2. Evaluate f1(x2)f^{-1}(x - 2): Substitute x2x - 2 into f1(x)f^{-1}(x): f1(x2)=2(x2)4(x2)+3.f^{-1}(x - 2) = \frac{2 - (x - 2)}{4(x - 2) + 3}. Simplify the numerator: 2(x2)=2x+2=4x.2 - (x - 2) = 2 - x + 2 = 4 - x. Simplify the denominator: 4(x2)+3=4x8+3=4x5.4(x - 2) + 3 = 4x - 8 + 3 = 4x - 5. Therefore: f1(x2)=4x4x5.f^{-1}(x - 2) = \frac{4 - x}{4x - 5}.


Final Answer:

f1(x2)=4x4x5.f^{-1}(x - 2) = \frac{4 - x}{4x - 5}.

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Related Questions:

  1. How do you verify if two functions are inverses of each other?
  2. What are the properties of inverse functions?
  3. How do we find the domain and range of f1(x)f^{-1}(x)?
  4. What happens if f(x)f(x) is not one-to-one? Can it still have an inverse?
  5. How do transformations like f(xa)f(x - a) affect the inverse function?

Tip:

Always verify an inverse function by substituting it back into the original function: f(f1(x))=xf(f^{-1}(x)) = x and f1(f(x))=xf^{-1}(f(x)) = x.

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Math Problem Analysis

Mathematical Concepts

Inverse Functions
Rational Functions
Algebraic Manipulation

Formulas

y = (2 - 3x) / (4x + 1)
f^(-1)(x) = (2 - x) / (4x + 3)
f^(-1)(x - 2) = (4 - x) / (4x - 5)

Theorems

Inverse Function Theorem

Suitable Grade Level

Grades 11-12