Math Problem Statement

If f left parenthesis x right parenthesis equals x squared minus 20 and g left parenthesis x right parenthesis equals 4 plus 3 x, then f left parenthesis g left parenthesis short dash 3 right parenthesis right parenthesis = __________.

Solution

We are tasked with evaluating f(g(3))f(g(-3)).

Given functions:

  • f(x)=x220f(x) = x^2 - 20
  • g(x)=4+3xg(x) = 4 + 3x

Let's break it down:

  1. First, find g(3)g(-3): g(3)=4+3(3)=49=5g(-3) = 4 + 3(-3) = 4 - 9 = -5

  2. Now, plug g(3)=5g(-3) = -5 into f(x)f(x): f(5)=(5)220=2520=5f(-5) = (-5)^2 - 20 = 25 - 20 = 5

Thus, f(g(3))=5f(g(-3)) = 5.


Would you like more details or explanations on this solution? Here are some related questions to explore:

  1. How would the result change if the function g(x)g(x) were different?
  2. How do we handle the composition of two functions in general?
  3. What would happen if we substituted another value into g(x)g(x)?
  4. How do you evaluate compositions when functions involve more complex expressions?
  5. What’s the significance of function composition in real-life scenarios?

Tip: When working with function compositions, always remember to first evaluate the inner function and then substitute its result into the outer function!

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra
Evaluation of Functions

Formulas

f(x) = x^2 - 20
g(x) = 4 + 3x

Theorems

Composition of Functions

Suitable Grade Level

Grades 9-11