Chapter 5: Problem 55
Graph each function. Give the domain and range. \(f(x)=-2 x+1\)
Short Answer
Expert verified
The domain is \((-∞, ∞)\) and the range is \((-∞, ∞)\).
Step by step solution
01
Understand the function
Recognize that the function given is a linear function of the form \(f(x) = mx + b\). Here, \(m = -2\) and \(b = 1\).
02
Identify the slope and y-intercept
The coefficient of \(x\) is \(-2\), which is the slope of the line. The \(y\)-intercept is \(1\) (where the line crosses the \(y\)-axis).
03
Plot the y-intercept
Begin by plotting the point \((0, 1)\) on the graph. This is the point where the line crosses the \(y\)-axis.
04
Use the slope to find another point
From the point \((0, 1)\), use the slope \(-2\). This means for every 1 unit increase in \(x\), \(f(x)\) decreases by 2 units. Hence, from \((0, 1)\), moving 1 unit to the right (\(x = 1\)), plot the point \((1, -1)\).
05
Draw the line
Draw a straight line through the points \((0, 1)\) and \((1, -1)\) to extend in both directions.
06
Determine the domain
Since the function is linear, the domain is all real numbers. This can be written as \((-\b+infty}, \b+infty})\).
07
Determine the range
Similarly, the range of a linear function is all real numbers. This can be written as \(\b+(-\b+infty}, \b+infty})\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Domain and Range
The domain and range of a linear function are core concepts in understanding how the function behaves.
For a linear function like \(f(x) = -2x + 1\), both the domain and range are all real numbers. This is because a linear function extends infinitely in both the positive and negative directions of the x-axis and y-axis.
Simply put, there are no restrictions on the values that x and y can take.
You can write the domain as \((-\infty, \infty)\)\. Similarly, the range is also \((-\infty, \infty)\).
This makes it easy to understand that linear functions cover all possible input (x) and output (y) values.
For a linear function like \(f(x) = -2x + 1\), both the domain and range are all real numbers. This is because a linear function extends infinitely in both the positive and negative directions of the x-axis and y-axis.
Simply put, there are no restrictions on the values that x and y can take.
You can write the domain as \((-\infty, \infty)\)\. Similarly, the range is also \((-\infty, \infty)\).
This makes it easy to understand that linear functions cover all possible input (x) and output (y) values.
Y-Intercept
The y-intercept of a linear function is the point where the graph crosses the y-axis.
In our function \(f(x) = -2x + 1\), the y-intercept is 1, because this is the constant term that stands alone without an x attached.
To graphically find this, plot the point \(0, 1\) on the graph.
This means when x is zero, f(x) is equal to 1.
Understanding the y-intercept helps in quickly plotting the initial point of the linear graph.
In our function \(f(x) = -2x + 1\), the y-intercept is 1, because this is the constant term that stands alone without an x attached.
To graphically find this, plot the point \(0, 1\) on the graph.
This means when x is zero, f(x) is equal to 1.
Understanding the y-intercept helps in quickly plotting the initial point of the linear graph.
Slope
The slope of a linear function indicates how steep the line is and the direction it moves.
For our function \(f(x) = -2x + 1\), the slope is -2. The slope is the coefficient of x in the equation.
This tells us that for every 1 unit increase in x, the value of f(x) decreases by 2 units.
Starting from the y-intercept \(0, 1\), if you move 1 unit to the right (x = 1), f(x) drops to -1.
This can be observed by plotting the point (1, -1).
Connecting the two points \(0, 1\) and \(1, -1\) with a straight line will give you the graph of the function.
For our function \(f(x) = -2x + 1\), the slope is -2. The slope is the coefficient of x in the equation.
This tells us that for every 1 unit increase in x, the value of f(x) decreases by 2 units.
Starting from the y-intercept \(0, 1\), if you move 1 unit to the right (x = 1), f(x) drops to -1.
This can be observed by plotting the point (1, -1).
Connecting the two points \(0, 1\) and \(1, -1\) with a straight line will give you the graph of the function.