Math Problem Statement

Determine whether functions f and g are inverse functions. 

fx2x5   gxx52 

Solution

To determine whether f(x)=2x+5f(x) = 2x + 5 and g(x)=x52g(x) = \frac{x - 5}{2} are inverse functions, we need to check whether f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x.

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

Substitute g(x)=x52g(x) = \frac{x - 5}{2} into f(x)=2x+5f(x) = 2x + 5: f(g(x))=2(x52)+5f(g(x)) = 2\left(\frac{x - 5}{2}\right) + 5 Simplify: f(g(x))=(x5)+5=xf(g(x)) = (x - 5) + 5 = x

Step 2: Check g(f(x))g(f(x))

Substitute f(x)=2x+5f(x) = 2x + 5 into g(x)=x52g(x) = \frac{x - 5}{2}: g(f(x))=(2x+5)52g(f(x)) = \frac{(2x + 5) - 5}{2} Simplify: g(f(x))=2x2=xg(f(x)) = \frac{2x}{2} = x

Conclusion:

Since both f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x, the functions f(x)=2x+5f(x) = 2x + 5 and g(x)=x52g(x) = \frac{x - 5}{2} are inverse functions.

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Related Questions:

  1. How do you find the inverse of a function algebraically?
  2. What are the conditions for two functions to be inverses?
  3. How do graphs of inverse functions relate to each other?
  4. How does the domain of a function relate to the range of its inverse?
  5. What is the importance of one-to-one functions in inverses?

Tip:

When verifying inverse functions, always confirm both f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x to avoid errors!

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Math Problem Analysis

Mathematical Concepts

Inverse Functions
Function Composition
Algebra

Formulas

f(g(x)) = x
g(f(x)) = x
f(x) = 2x + 5
g(x) = (x - 5)/2

Theorems

Inverse Function Theorem

Suitable Grade Level

Grades 9-12