Math Problem Statement

If f(x) = x^2 + 4x + 8, what is f(-1)?

Solution

The question asks you to evaluate f(1)f(-1) for the given quadratic function f(x)=x2+4x+8f(x) = x^2 + 4x + 8.

Steps:

  1. Substitute x=1x = -1 into f(x)=x2+4x+8f(x) = x^2 + 4x + 8: f(1)=(1)2+4(1)+8f(-1) = (-1)^2 + 4(-1) + 8

  2. Simplify each term: f(1)=14+8f(-1) = 1 - 4 + 8

  3. Combine the terms: f(1)=1+84=5f(-1) = 1 + 8 - 4 = 5

Final Answer:

The value of f(1)f(-1) is 5, so the correct choice is Item 3.


Would you like further explanation or related details? Here are some follow-up questions to expand your understanding:

  1. How is the value of f(1)f(-1) calculated for a polynomial function?
  2. What does the graph of f(x)=x2+4x+8f(x) = x^2 + 4x + 8 look like?
  3. How do the coefficients of a quadratic function affect its shape?
  4. How would you find the vertex of f(x)=x2+4x+8f(x) = x^2 + 4x + 8?
  5. Can the same substitution process be used for higher-degree polynomials?

Tip: When substituting a value into a function, be careful with signs and order of operations (e.g., exponents before multiplication or addition).

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Function Evaluation

Formulas

f(x) = ax^2 + bx + c

Theorems

Substitution Method

Suitable Grade Level

Grades 8-10