Math Problem Statement

jawablah pertanyaan berikut

Diketahui f(x) = 3x - 1 dan g(x) = x^2 - 2x - 5. Fungsi komposisi (g o f)(x) = ...

Solution

The question asks for the composition of two functions, g(f(x))g(f(x)), given the following:

  • f(x)=3x1f(x) = 3x - 1
  • g(x)=x22x5g(x) = x^2 - 2x - 5

We are tasked with finding g(f(x))g(f(x)), meaning we substitute f(x)f(x) into g(x)g(x).

Step-by-step solution:

  1. Substitute f(x)=3x1f(x) = 3x - 1 into g(x)g(x): g(f(x))=g(3x1)g(f(x)) = g(3x - 1)

  2. Now apply the function g(x)=x22x5g(x) = x^2 - 2x - 5, replacing xx with 3x13x - 1: g(3x1)=(3x1)22(3x1)5g(3x - 1) = (3x - 1)^2 - 2(3x - 1) - 5

  3. Expand the squared term: (3x1)2=(3x)22(3x)(1)+(1)2=9x26x+1(3x - 1)^2 = (3x)^2 - 2(3x)(1) + (1)^2 = 9x^2 - 6x + 1

  4. Simplify the linear term: 2(3x1)=6x+2-2(3x - 1) = -6x + 2

  5. Now substitute these into the original expression: g(3x1)=9x26x+16x+25g(3x - 1) = 9x^2 - 6x + 1 - 6x + 2 - 5

  6. Simplify the expression: g(3x1)=9x212x+(1+25)=9x212x2g(3x - 1) = 9x^2 - 12x + (1 + 2 - 5) = 9x^2 - 12x - 2

Thus, g(f(x))=9x212x2g(f(x)) = 9x^2 - 12x - 2.

Conclusion:

The correct answer is option E: 9x212x29x^2 - 12x - 2.


Do you need more details or have any questions? Here are 5 related questions to expand your understanding:

  1. How would you compute f(g(x))f(g(x)) for the same functions?
  2. Can you describe the general process of function composition?
  3. How does expanding binomials help in solving function compositions?
  4. What is the difference between g(f(x))g(f(x)) and f(g(x))f(g(x))?
  5. How would you solve this problem if one of the functions were a trigonometric function?

Tip: When composing functions, always substitute one function's result into the other carefully to avoid errors in simplification.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Quadratic Expressions
Algebraic Manipulation

Formulas

(g o f)(x) = g(f(x))
Expanding Binomials
Simplifying Expressions

Theorems

Function Composition Theorem
Binomial Expansion

Suitable Grade Level

Grades 9-11