Chapter 10: Problem 49
Graph the line with the given equation. \(y+2=2(x-1)\)
Short Answer
Expert verified
Graph the line of \( y = 2x - 4 \) using points (0,-4) and (1,-2).
Step by step solution
01
Simplify the Equation
Begin by simplifying the given equation to the slope-intercept form, which is \( y = mx + b \). Start by distributing the 2 on the right side: \[ y + 2 = 2(x - 1) \] This becomes: \[ y + 2 = 2x - 2 \] Next, subtract 2 from both sides to isolate \( y \): \[ y = 2x - 4 \] The equation is now in the form \( y = mx + b \) with \( m = 2 \) (the slope) and \( b = -4 \) (the y-intercept).
02
Identify the Y-Intercept
The y-intercept \( b \) is the point where the line crosses the y-axis. From the equation \( y = 2x - 4 \), we can see that \( b = -4 \). This tells us that the line crosses the y-axis at the point (0, -4). Plot this point on a graph.
03
Use the Slope to Find Another Point
The slope \( m = 2 \) means that for every 1 unit increase in \( x \), the value of \( y \) increases by 2 units. Starting from the y-intercept (0, -4), move 1 unit to the right to \( x = 1 \) and 2 units up to \( y = -2 \). This gives us another point on the line: (1, -2).
04
Draw the Line
With the points (0, -4) and (1, -2) plotted, draw a straight line through these points. Extend the line in both directions, using a ruler to ensure accuracy. This visualizes the graph of the equation \( y = 2x - 4 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Slope-Intercept Form
The slope-intercept form of a linear equation is particularly useful for graphing lines. It's written as \( y = mx + b \). Here, \( m \) represents the slope of the line, while \( b \) is the y-intercept. This form is straightforward because it clearly shows the slope and where the line crosses the y-axis. For beginners, converting any linear equation to this form simplifies the process of graphing. To identify the components quickly, look for the coefficient of \( x \) which gives you the slope, and the constant term which indicates the y-intercept. This makes plotting the line intuitive.
Slope
The slope of a line is a measure of its steepness and direction. From the equation \( y = mx + b \), \( m \) is the slope. A positive value indicates the line rises as it moves from left to right, while a negative value means it falls. A slope of zero creates a horizontal line, and an undefined slope corresponds to a vertical line.
Calculating the slope as 'rise over run' helps to visually plot the line. For instance, a slope of 2 means for every 1 unit you move to the right (run), you move 2 units up (rise). Understanding this concept assists in accurately plotting additional points once you know the y-intercept.
Calculating the slope as 'rise over run' helps to visually plot the line. For instance, a slope of 2 means for every 1 unit you move to the right (run), you move 2 units up (rise). Understanding this concept assists in accurately plotting additional points once you know the y-intercept.
Y-Intercept
The y-intercept is the point where the line crosses the y-axis. In the equation \( y = mx + b \), \( b \) represents this intercept. For graphing, it acts as the initial point to start with on the graph. Simply locate this point on the y-axis. Knowing the y-intercept allows you to set the foundation for the line.
For example, if the y-intercept is -4, like in the exercise, you start plotting your line at point (0, -4). From there, using the slope, you can determine the direction of your line. Defining this intercept accurately is crucial for drawing the correct graph.
For example, if the y-intercept is -4, like in the exercise, you start plotting your line at point (0, -4). From there, using the slope, you can determine the direction of your line. Defining this intercept accurately is crucial for drawing the correct graph.
Graphing Techniques
Graphing a line involves plotting it accurately on the coordinate plane. After identifying the slope and y-intercept, you can begin sketching the line. Start at the y-intercept point and use the slope to find additional points. Plot the initial point (0, -4) based on the intercept. Then apply the slope, in this case, 2, to move from one point to the next.
Use a ruler to connect these points with a straight line. Extending the line in both directions showcases the linear equation fully. Ensuring precision when plotting results in more accurate and easy-to-read graphs. Small adjustments can lead to big differences in understanding linear relationships on a graph.
Use a ruler to connect these points with a straight line. Extending the line in both directions showcases the linear equation fully. Ensuring precision when plotting results in more accurate and easy-to-read graphs. Small adjustments can lead to big differences in understanding linear relationships on a graph.