Math Problem Statement

Evaluate the function for f(x) = x + 3 and g(x) = x^2 - 2. Find (fg)(-8).

Solution

To solve (fg)(8)(fg)(-8), where f(x)=x+3f(x) = x + 3 and g(x)=x22g(x) = x^2 - 2, we need to evaluate the product of the functions f(x)f(x) and g(x)g(x) at x=8x = -8.

Step-by-step solution:

  1. Find f(8)f(-8): f(x)=x+3f(x) = x + 3 Substituting x=8x = -8: f(8)=8+3=5f(-8) = -8 + 3 = -5

  2. Find g(8)g(-8): g(x)=x22g(x) = x^2 - 2 Substituting x=8x = -8: g(8)=(8)22=642=62g(-8) = (-8)^2 - 2 = 64 - 2 = 62

  3. Multiply the results: Now, (fg)(8)(fg)(-8) is the product of f(8)f(-8) and g(8)g(-8): (fg)(8)=f(8)×g(8)=5×62=310(fg)(-8) = f(-8) \times g(-8) = -5 \times 62 = -310

So, (fg)(8)=310(fg)(-8) = -310.

Would you like any further details or clarifications?

Here are 5 related questions:

  1. How do you find the sum of two functions at a particular value?
  2. How would the result change if the function g(x)g(x) had a different power (e.g., g(x)=x32g(x) = x^3 - 2)?
  3. What is the domain of the function product f(x)g(x)f(x) \cdot g(x)?
  4. How can we graph the function f(x)g(x)f(x) \cdot g(x) for all xx?
  5. Can this process be extended to more complicated functions, such as trigonometric functions?

Tip: When multiplying functions, always evaluate each function individually first before performing any operations on the results!

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Math Problem Analysis

Mathematical Concepts

Function Evaluation
Algebra
Product of Functions

Formulas

f(x) = x + 3
g(x) = x^2 - 2
(fg)(x) = f(x) * g(x)

Theorems

Function Evaluation

Suitable Grade Level

Grades 9-12