Math Problem Statement

Let f(x) = 2x^2 - 8x + 5 and g(x) = x^2 + 16. Find (f + g)(x), (f - g)(x), and (f * g)(x).

Solution

Let's break down the given problem based on the image.

You are given two functions:

f(x)=2x28x+5f(x) = 2x^2 - 8x + 5 g(x)=x2+16g(x) = x^2 + 16

You are asked to find three different operations involving these functions:

a) (f+g)(x)(f + g)(x)

This is the sum of the two functions, f(x)+g(x)f(x) + g(x).

(f+g)(x)=(2x28x+5)+(x2+16)(f + g)(x) = (2x^2 - 8x + 5) + (x^2 + 16)

Simplify the expression:

(f+g)(x)=2x2+x28x+5+16(f + g)(x) = 2x^2 + x^2 - 8x + 5 + 16

(f+g)(x)=3x28x+21(f + g)(x) = 3x^2 - 8x + 21

b) (fg)(x)(f - g)(x)

This is the difference between the two functions, f(x)g(x)f(x) - g(x).

(fg)(x)=(2x28x+5)(x2+16)(f - g)(x) = (2x^2 - 8x + 5) - (x^2 + 16)

Simplify the expression:

(fg)(x)=2x2x28x+516(f - g)(x) = 2x^2 - x^2 - 8x + 5 - 16

(fg)(x)=x28x11(f - g)(x) = x^2 - 8x - 11

c) (fg)(x)(f \cdot g)(x)

This is the product of the two functions, f(x)g(x)f(x) \cdot g(x).

(fg)(x)=(2x28x+5)(x2+16)(f \cdot g)(x) = (2x^2 - 8x + 5)(x^2 + 16)

Expand this by distributing each term:

(fg)(x)=2x2(x2+16)8x(x2+16)+5(x2+16)(f \cdot g)(x) = 2x^2(x^2 + 16) - 8x(x^2 + 16) + 5(x^2 + 16)

Now, distribute each term:

=2x4+32x28x3128x+5x2+80= 2x^4 + 32x^2 - 8x^3 - 128x + 5x^2 + 80

Simplify the terms:

(fg)(x)=2x48x3+37x2128x+80(f \cdot g)(x) = 2x^4 - 8x^3 + 37x^2 - 128x + 80

Final Answers:

  • (f+g)(x)=3x28x+21(f + g)(x) = 3x^2 - 8x + 21
  • (fg)(x)=x28x11(f - g)(x) = x^2 - 8x - 11
  • (fg)(x)=2x48x3+37x2128x+80(f \cdot g)(x) = 2x^4 - 8x^3 + 37x^2 - 128x + 80

Would you like further details or explanations on any part of this? Here are five related questions you can try:

  1. How do you find the quotient of two functions, (f/g)(x)(f / g)(x)?
  2. What are the domain restrictions for each function f(x)f(x) and g(x)g(x)?
  3. How would you evaluate (f+g)(2)(f + g)(2)?
  4. What are the critical points of f(x)f(x) and g(x)g(x)?
  5. How do you find the composition of the functions, such as f(g(x))f(g(x))?

Tip: When adding or subtracting functions, remember to combine like terms to simplify the expression properly.

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomial Functions
Function Operations

Formulas

(f + g)(x) = f(x) + g(x)
(f - g)(x) = f(x) - g(x)
(f * g)(x) = f(x) * g(x)

Theorems

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Suitable Grade Level

Grades 10-12