Chapter 2: Problem 20
Construct an equation and sketch the graph of its line with the given slope, \(m,\) and vertical intercept, \(b .\) (Hint: Find two points on the line.) a. \(m=2, b=-3\) b. \(m=-\frac{3}{4}, b=1\) c. \(m=0, b=50\)
Short Answer
Expert verified
a.\( y = 2x - 3 \); b.\( y = -\frac{3}{4}x + 1 \); c.\( y = 50 \).
Step by step solution
01
- Understand the Equation of a Line
The general form of a linear equation is given by: \[ y = mx + b \]where \( m \) is the slope and \( b \) is the y-intercept. Given the values of \( m \) and \( b \), we can construct the equation of the line.
02
- Construct the Equation for Part (a)
Given: \( m = 2 \) and \( b = -3 \). Substitute these values into the general form: \[ y = 2x - 3 \]
03
- Find Two Points for Part (a)
To sketch the line, find two points. Let's choose two values for x and compute y.For \( x = 0 \): \[ y = 2(0) - 3 \]\[ y = -3 \]So, the point is (0, -3).For \( x = 1 \): \[ y = 2(1) - 3 \]\[ y = -1 \]So, the point is (1, -1).
04
- Sketch the Graph for Part (a)
Plot the points (0, -3) and (1, -1) on a graph and draw a line passing through them. This line represents the equation \( y = 2x - 3 \).
05
- Construct the Equation for Part (b)
Given: \( m = -\frac{3}{4} \) and \( b = 1 \). Substitute these values into the general form: \[ y = -\frac{3}{4}x + 1 \]
06
- Find Two Points for Part (b)
To sketch the line, find two points. Let's choose two values for x and compute y.For \( x = 0 \): \[ y = -\frac{3}{4}(0) + 1 \]\[ y = 1 \]So, the point is (0, 1).For \( x = 4 \): \[ y = -\frac{3}{4}(4) + 1 \]\[ y = -3 + 1 \]\[ y = -2 \]So, the point is (4, -2).
07
- Sketch the Graph for Part (b)
Plot the points (0, 1) and (4, -2) on a graph and draw a line passing through them. This line represents the equation \( y = -\frac{3}{4}x + 1 \).
08
- Construct the Equation for Part (c)
Given: \( m = 0 \) and \( b = 50 \). Substitute these values into the general form: \[ y = 0x + 50 \]\[ y = 50 \]
09
- Find Two Points for Part (c)
To sketch the line, find two points. Let's choose two values for x (since y is constant).For \( x = 0 \): \[ y = 50 \]So, the point is (0, 50).For \( x = 1 \): \[ y = 50 \]So, the point is (1, 50).
10
- Sketch the Graph for Part (c)
Plot the points (0, 50) and (1, 50) on a graph and draw a horizontal line passing through them. This line represents the equation \( y = 50 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
linear equations
Linear equations are fundamental in algebra. They describe a straight line in the coordinate system. The general form of a linear equation is given by \( y = mx + b \). Here, \( y \) represents the dependent variable, \( x \) represents the independent variable, \( m \) is the slope of the line, and \( b \) is the y-intercept.
The slope determines the steepness and the direction of the line, while the y-intercept is the point where the line crosses the y-axis. Every linear equation will graph as a straight line, and understanding how to form and graph these equations is a crucial skill in mathematics.
The slope determines the steepness and the direction of the line, while the y-intercept is the point where the line crosses the y-axis. Every linear equation will graph as a straight line, and understanding how to form and graph these equations is a crucial skill in mathematics.
slope-intercept form
The slope-intercept form of a linear equation is one of the most commonly used forms, expressed as \( y = mx + b \).
Here, \( m \) represents the slope of the line, and \( b \) is the y-intercept. This form is very useful because it provides immediate information about the slope and the y-intercept, making it easy to graph the line.
In the equation \( y = 2x - 3 \), for example, the slope \( m \) is 2, meaning the line rises 2 units for every 1 unit it moves to the right. The y-intercept \( b \) is -3, which tells us the line crosses the y-axis at -3. This concise format makes it simple to construct and understand the behavior of the line.
Here, \( m \) represents the slope of the line, and \( b \) is the y-intercept. This form is very useful because it provides immediate information about the slope and the y-intercept, making it easy to graph the line.
In the equation \( y = 2x - 3 \), for example, the slope \( m \) is 2, meaning the line rises 2 units for every 1 unit it moves to the right. The y-intercept \( b \) is -3, which tells us the line crosses the y-axis at -3. This concise format makes it simple to construct and understand the behavior of the line.
graphing lines
Graphing a line involves plotting points and drawing a straight line through them. Begin by identifying the slope and y-intercept from the equation in the slope-intercept form.
For example, given the equation \( y = 2x - 3 \), the slope is 2 and the y-intercept is -3.
Start by plotting the y-intercept on the graph (0, -3). This is where the line crosses the y-axis. Next, use the slope to find another point. A slope of 2 means that for every 1 unit you move to the right on the x-axis, you move up 2 units on the y-axis.
Plot this second point, which in this case would be (1, -1). Finally, draw a straight line through these points. Repeat the process for other equations to visualize different lines on the graph.
For example, given the equation \( y = 2x - 3 \), the slope is 2 and the y-intercept is -3.
Start by plotting the y-intercept on the graph (0, -3). This is where the line crosses the y-axis. Next, use the slope to find another point. A slope of 2 means that for every 1 unit you move to the right on the x-axis, you move up 2 units on the y-axis.
Plot this second point, which in this case would be (1, -1). Finally, draw a straight line through these points. Repeat the process for other equations to visualize different lines on the graph.
y-intercept
The y-intercept is a key component of a linear equation. It is the point where the line crosses the y-axis, and it is represented by the \( b \) value in the slope-intercept form \( y = mx + b \).
For example, in the equation \( y = -\frac{3}{4}x + 1 \), the y-intercept is 1, meaning the line crosses the y-axis at (0, 1). The y-intercept provides a starting point for graphing the line.
By understanding the y-intercept, you can quickly determine where the line begins in the y-dimension, making it easier to graph the equation accurately and understand its behavior.
For example, in the equation \( y = -\frac{3}{4}x + 1 \), the y-intercept is 1, meaning the line crosses the y-axis at (0, 1). The y-intercept provides a starting point for graphing the line.
By understanding the y-intercept, you can quickly determine where the line begins in the y-dimension, making it easier to graph the equation accurately and understand its behavior.