Math Problem Statement

Consider the function f(x) = -2x - 8. What is the value of f(-5)?

Solution

Let’s solve the problem step by step.

The function given is:

f(x)=2x8f(x) = -2x - 8

We need to find f(5)f(-5), which means substituting x=5x = -5 into the function.

Step 1: Substitute x=5x = -5 into f(x)f(x)

f(5)=2(5)8f(-5) = -2(-5) - 8

Step 2: Simplify the expression

f(5)=108f(-5) = 10 - 8

f(5)=2f(-5) = 2

Final Answer:

The value of f(5)f(-5) is 2, so the correct option is:

2\boxed{2}


Would you like a deeper explanation or help with other questions? Here are 5 related questions to expand your understanding:

  1. How would the function change if the coefficient of xx were 3 instead of -2?
  2. What is the value of f(0)f(0) for this function?
  3. How do we interpret the slope (2-2) of the function geometrically?
  4. What would happen to the graph if the constant term 8-8 were changed to 10-10?
  5. How can you determine where f(x)=0f(x) = 0?

Tip: Always substitute carefully and simplify step-by-step to avoid calculation errors!

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Math Problem Analysis

Mathematical Concepts

Linear Functions
Substitution in Functions

Formulas

f(x) = mx + b

Theorems

Linear Equation Substitution

Suitable Grade Level

Grades 6-8