Chapter 3: Problem 88
Given the following, \(f(x)=-5 x+1,\) find \(f(-3)\)
Short Answer
Expert verified
The value of \(f(-3)\) is 16.
Step by step solution
01
Identify the Function
We are given the function, \(f(x) = -5x + 1\). This is a linear function with a slope of \(-5\) and a y-intercept of \(1\).
02
Substitute the Value into the Function
To find \(f(-3)\), substitute \(-3\) for \(x\) in the function: \(f(-3) = -5(-3) + 1\).
03
Simplify the Expression
Simplify the expression obtained from substitution: \(-5(-3) = 15\). So, \(f(-3) = 15 + 1\).
04
Perform the Final Calculation
Add 1 to 15: \(f(-3) = 15 + 1 = 16\). Therefore, the value of the function at \(x = -3\) is 16.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Function Evaluation
When working with functions in mathematics, function evaluation is a key concept. It involves determining the output or value of a function at a given input value. In our problem, we're given the function \(f(x) = -5x + 1\), and we're asked to find \(f(-3)\). This means we want to evaluate the function at \(x = -3\). Function evaluation helps us understand how the function behaves for specific inputs, which is crucial in various applications like economics, physics, and engineering. Evaluating a linear function like this one involves straightforward calculations, making it an ideal starting point for learning the basics of functions.
Substitution Method
The substitution method is a straightforward way to evaluate functions, especially linear ones. To use this method, you replace the variable \(x\) in the expression \(-5x + 1\) with \(-3\). This gives us \(f(-3) = -5(-3) + 1\).
- Find the replacement value, in this case, \(-3\).
- Replace all instances of \(x\) with \(-3\) in the expression.
Simplification Process
Simplification is the next essential step after substitution. It involves performing arithmetic operations to tidy up the expression. Once you have the substituted expression \(-5(-3) + 1\), you perform operations:
- Multiply: \(-5 \times -3 = 15\).
- Addition: \(15 + 1 = 16\).
Slope and Y-intercept
In linear functions, the slope and y-intercept are fundamental features that describe the line on a graph. For \(f(x) = -5x + 1\), the slope is \(-5\), indicating a downward trend—the function decreases five units vertically for every one unit increase horizontally. The y-intercept is \(1\), where the line crosses the y-axis. This function's behavior can be depicted visually as a line sloping downwards, starting from the point \(1\) on the y-axis. Understanding these components helps predict and interpret the function's graph even without calculating every point.