Chapter 1: Problem 3
Give the (a) \(x\) -intercept, (b) \(y\) -intercept, (c) domain, (d) range, and (e) slope of the line. Do not use a calculator. $$f(x)=3 x-6 \quad$$
Short Answer
Expert verified
x-intercept: (2, 0); y-intercept: (0, -6); domain: all real numbers; range: all real numbers; slope: 3.
Step by step solution
01
Finding the x-intercept
To find the x-intercept, set \( f(x) = 0 \) and solve for \( x \). For the function \( f(x) = 3x - 6 \):\[ 0 = 3x - 6 \]Add 6 to both sides:\[ 3x = 6 \]Divide by 3:\[ x = 2 \]So, the x-intercept is at \((2, 0)\).
02
Finding the y-intercept
To find the y-intercept, set \( x = 0 \) and solve for \( f(x) \). Substitute \( x = 0 \) into the equation:\[ f(0) = 3(0) - 6 \]So, \( f(0) = -6 \).The y-intercept is at \((0, -6)\).
03
Determining the Domain
The domain of a linear function like \( f(x) = 3x - 6 \) includes all real numbers, because there are no restrictions on the value of \( x \). Therefore, the domain is \(( -\infty, \infty )\).
04
Determining the Range
The range of a linear function like \( f(x) = 3x - 6 \) is also all real numbers, because the line extends infinitely in both vertical directions. Therefore, the range is \(( -\infty, \infty )\).
05
Calculating the Slope
The function \( f(x) = 3x - 6 \) is already in the slope-intercept form \( y = mx + b \). In this form, \( m \) represents the slope. Thus, the slope of the line is \( 3 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding the X-Intercept
When working with a linear function like the one given in the exercise, finding the x-intercept is simple and straightforward. The x-intercept is the point where the graph of the function crosses the x-axis. This is the point where the output, also known as the function value, is zero. In mathematical terms, it's where \( f(x) = 0 \).
To find this x-intercept for the function \( f(x) = 3x - 6 \), you set the equation to zero and solve for \( x \). This means you solve \( 0 = 3x - 6 \), which leads to \( x = 2 \) after solving the equation.
The coordinates of the x-intercept are therefore \( (2, 0) \), because it's a point on the graph where the y-value, representing the output of the function, is zero.
To find this x-intercept for the function \( f(x) = 3x - 6 \), you set the equation to zero and solve for \( x \). This means you solve \( 0 = 3x - 6 \), which leads to \( x = 2 \) after solving the equation.
The coordinates of the x-intercept are therefore \( (2, 0) \), because it's a point on the graph where the y-value, representing the output of the function, is zero.
Grasping the Y-Intercept
The y-intercept of a linear function is equally easy to understand as the x-intercept. It's the point where the function crosses the y-axis, which happens when the x-value is zero. In practical terms, you find this by plugging in zero for \( x \) in the equation and solving for \( f(x) \), or \( y \).
For the function \( f(x) = 3x - 6 \), substitute \( x = 0 \) into the equation, resulting in \( f(0) = -6 \). Thus, the y-intercept is at the point \( (0, -6) \).
For the function \( f(x) = 3x - 6 \), substitute \( x = 0 \) into the equation, resulting in \( f(0) = -6 \). Thus, the y-intercept is at the point \( (0, -6) \).
- This means the graph touches the y-axis at the point where the y-value is -6.
Domain and Range of Linear Functions
Linear functions are defined everywhere on the real number line, which means their domain is all real numbers. For the function \( f(x) = 3x - 6 \), there are no restrictions on the values that \( x \) can take. Hence, the domain is represented as \(( -\infty, \infty )\).
In simple terms, for every x-value, there's a corresponding y-value, meaning the line continues forever along the y-axis.
- The function has no breaks, holes, or gaps within the real numbers.
In simple terms, for every x-value, there's a corresponding y-value, meaning the line continues forever along the y-axis.
Determining the Slope of a Line
The slope is a crucial aspect of the linear function, indicating how steep the line is and in which direction it inclines. A positive slope means the line rises as it goes from left to right, while a negative slope means the line falls.For the function \( f(x) = 3x - 6 \), it's in the form \( y = mx + b \), where \( m \) is the slope. Here, \( m = 3 \), indicating that for every one unit increase in \( x \), \( y \) increases by 3 units.
- This is described as a slope of 3, a moderate incline showing how rapidly y increases with x.