Math Problem Statement

find (f+g)(8) if f(x)=5x2-3x+1 and g(x)=4x2+8x-11

Solution

To find (f+g)(8)(f+g)(8), we first need to add the two given functions f(x)f(x) and g(x)g(x), and then evaluate the result at x=8x = 8.

Given:

  • f(x)=5x23x+1f(x) = 5x^2 - 3x + 1
  • g(x)=4x2+8x11g(x) = 4x^2 + 8x - 11

Step 1: Add the functions:

(f+g)(x)=f(x)+g(x)(f + g)(x) = f(x) + g(x) (f+g)(x)=(5x23x+1)+(4x2+8x11)(f + g)(x) = (5x^2 - 3x + 1) + (4x^2 + 8x - 11)

Now, combine like terms: (f+g)(x)=(5x2+4x2)+(3x+8x)+(111)(f + g)(x) = (5x^2 + 4x^2) + (-3x + 8x) + (1 - 11) (f+g)(x)=9x2+5x10(f + g)(x) = 9x^2 + 5x - 10

Step 2: Evaluate (f+g)(x)(f + g)(x) at x=8x = 8:

(f+g)(8)=9(8)2+5(8)10(f + g)(8) = 9(8)^2 + 5(8) - 10 (f+g)(8)=9(64)+4010(f + g)(8) = 9(64) + 40 - 10 (f+g)(8)=576+4010(f + g)(8) = 576 + 40 - 10 (f+g)(8)=606(f + g)(8) = 606

Final Answer:

(f+g)(8)=606(f + g)(8) = 606

Would you like a more detailed explanation or have any other questions?

Here are 5 related questions:

  1. What is the general process to combine two functions?
  2. How would you find f(x)g(x)f(x) \cdot g(x) for these functions?
  3. How does the degree of the polynomial affect the graph of f(x)+g(x)f(x) + g(x)?
  4. How do we determine the zeros of f(x)+g(x)f(x) + g(x)?
  5. How do you find the inverse of a function?

Tip: Always check your algebraic simplifications carefully, especially when combining like terms!

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomials
Function Addition

Formulas

f(x) + g(x) = (a_1x^2 + b_1x + c_1) + (a_2x^2 + b_2x + c_2)
Evaluating functions: f(a)

Theorems

Basic Polynomial Addition
Function Evaluation

Suitable Grade Level

Grades 9-10