Math Problem Statement

Let f(x)=x^2-4 and g(x)=3x+2 , evaluate the following. f(-3)= f(-3)+g(x)= f(g(3))= g(f(3))=

Solution

Let's solve each part step by step:

1. f(3)f(-3)

The function f(x)=x24f(x) = x^2 - 4. To find f(3)f(-3), substitute x=3x = -3 into the function: f(3)=(3)24=94=5f(-3) = (-3)^2 - 4 = 9 - 4 = 5 So, f(3)=5f(-3) = 5.

2. f(3)+g(x)f(-3) + g(x)

We already know f(3)=5f(-3) = 5. Now, we need to find the expression for g(x)g(x). The function g(x)=3x+2g(x) = 3x + 2. So, f(3)+g(x)=5+(3x+2)=5+3x+2=7+3xf(-3) + g(x) = 5 + (3x + 2) = 5 + 3x + 2 = 7 + 3x Thus, f(3)+g(x)=7+3xf(-3) + g(x) = 7 + 3x.

3. f(g(3))f(g(3))

We need to find g(3)g(3) first. Using g(x)=3x+2g(x) = 3x + 2: g(3)=3(3)+2=9+2=11g(3) = 3(3) + 2 = 9 + 2 = 11 Now, substitute g(3)=11g(3) = 11 into f(x)f(x): f(g(3))=f(11)=1124=1214=117f(g(3)) = f(11) = 11^2 - 4 = 121 - 4 = 117 Thus, f(g(3))=117f(g(3)) = 117.

4. g(f(3))g(f(3))

We need to find f(3)f(3) first. Using f(x)=x24f(x) = x^2 - 4: f(3)=324=94=5f(3) = 3^2 - 4 = 9 - 4 = 5 Now, substitute f(3)=5f(3) = 5 into g(x)g(x): g(f(3))=g(5)=3(5)+2=15+2=17g(f(3)) = g(5) = 3(5) + 2 = 15 + 2 = 17 Thus, g(f(3))=17g(f(3)) = 17.

Final Answers:

  • f(3)=5f(-3) = 5
  • f(3)+g(x)=7+3xf(-3) + g(x) = 7 + 3x
  • f(g(3))=117f(g(3)) = 117
  • g(f(3))=17g(f(3)) = 17

Would you like further details on any of the steps? Or do you have any questions?

Here are some related questions you might find interesting:

  1. What is the general form for composing two functions like f(g(x))f(g(x))?
  2. How do you find the inverse of a function like g(x)=3x+2g(x) = 3x + 2?
  3. How do you solve a quadratic function for xx?
  4. What is the difference between evaluating a function and composing two functions?
  5. How does function composition relate to real-world problems?

Tip: When composing functions, always evaluate the "inner" function first, then apply the result to the "outer" function.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Function Evaluation
Function Composition
Algebra

Formulas

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

Theorems

Function Composition Theorem

Suitable Grade Level

Grades 8-10