Math Problem Statement

If f(x) = 2x^2 - 1 and g(x) = 2x + 1, evaluate f(g(x)) when x = -3.

Solution

We are given two functions, f(x)=2x21f(x) = 2x^2 - 1 and g(x)=2x+1g(x) = 2x + 1, and we are asked to evaluate f(g(x))f(g(x)) when x=3x = -3.

Step 1: Evaluate g(x)g(x) at x=3x = -3

Using the function g(x)=2x+1g(x) = 2x + 1:

g(3)=2(3)+1=6+1=5g(-3) = 2(-3) + 1 = -6 + 1 = -5

Step 2: Evaluate f(x)f(x) at x=5x = -5

Now, substitute g(3)=5g(-3) = -5 into f(x)=2x21f(x) = 2x^2 - 1:

f(5)=2(5)21=2(25)1=501=49f(-5) = 2(-5)^2 - 1 = 2(25) - 1 = 50 - 1 = 49

Thus, f(g(3))=49f(g(-3)) = 49.

The correct answer is 49.

Would you like more details or have any questions?

Here are some related questions you might find helpful:

  1. How do you evaluate compositions of functions?
  2. What are common mistakes when working with function compositions?
  3. Can you explain how to graph the composition of functions?
  4. How does the domain of a function affect its composition?
  5. How do you reverse a composition of functions?

Tip: Always evaluate the inner function first when working with compositions.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Quadratic Functions
Linear Functions

Formulas

f(x) = 2x^2 - 1
g(x) = 2x + 1

Theorems

Composition of Functions

Suitable Grade Level

Grades 9-10