Chapter 3: Problem 34
For each function \(f,\) find \((a) f(2),(b) f(0),\) and \((c) f(-3) .\) See Example 5 $$ f(x)=-3 x+5 $$
Short Answer
Expert verified
f(2) = -1, f(0) = 5, f(-3) = 14.
Step by step solution
01
- Understand the Function
The given function is \( f(x) = -3x + 5 \). This means for any input \( x \), the output \( f(x) \) can be calculated by multiplying \( x \) by \( -3 \) and then adding \( 5 \).
02
- Calculate \( f(2) \)
Substitute \( 2 \) for \( x \) in the function \( f \): \[ f(2) = -3(2) + 5 \] Simplify the expression: \[ f(2) = -6 + 5 = -1 \].
03
- Calculate \( f(0) \)
Substitute \( 0 \) for \( x \) in the function \( f \): \[ f(0) = -3(0) + 5 \] Simplify the expression: \[ f(0) = 0 + 5 = 5 \].
04
- Calculate \( f(-3) \)
Substitute \( -3 \) for \( x \) in the function \( f \): \[ f(-3) = -3(-3) + 5 \] Simplify the expression: \[ f(-3) = 9 + 5 = 14 \].
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding Linear Functions
A linear function is one where each input is multiplied by a constant and then another constant is added. For example, in the function given in the exercise, \texpressed as \[ f(x) = -3x + 5 \], the term \[ -3x \] shows that each input \( x \) is multiplied by \( -3 \),\tand then 5 is added to that product. The general formula for a linear function is \[ f(x) = mx + b \], where \( m \) represents the slope and \( b \) is the y-intercept. Linear functions are important because:\t
\t
- \t
- They grow at a constant rate, making them predictable and easy to graph. \t
- They can represent many real-world situations, such as calculating costs or speeds that change linearly. \t
\t
Substitution Method
Substitution is a technique where we replace one variable with a specific value to find the outcome. In the given function \[ f(x) = -3x + 5 \], to find \[ f(2) \], \twe substitute 2 into the function in place of \( x \). This means that \[ f(2) = -3(2) + 5 \]. Here, the variable \( x \) is replaced with 2, and then the expression is solved step by step. By replacing the variable with a given number:\t
\t
- \t
- We can directly find the function's value at specific points. \t
- This method makes it easier to calculate outcomes without graphing. \t
- \t
- For \( f(2) \): Substituted 2, the result is \[ f(2) = -6 + 5 = -1 \]. \t
- For \( f(0) \): Substituted 0, the result is \[ f(0) = 0 + 5 = 5 \]. \t
- For \( f(-3) \): Substituted -3, the result is \[ f(-3) = 9 + 5 = 14 \]. \t
\t
Simplifying Expressions
Simplification involves reducing an expression to its simplest form. This means combining like terms, applying arithmetic operations, and making the expression as compact as possible. \tFor the function \[ f(x) = -3x + 5 \], after substituting the variable with a number, like \[ f(2) = -3(2) + 5 \], simplifying involves:\t
- \t
- Multiplying \( -3 \times 2 \), which gives -6. \t
- Then adding 5 to -6, resulting in -1. \t
- \t
- Clearly understanding the result of a function. \t
- Ensuring that the calculations are accurate and errors minimized. \t
- Simplifying and solving complex mathematical problems easily. \t