Chapter 2: Problem 31
Give the slope and y-intercept of each line, and graph it. $$4 x-y=7$$
Short Answer
Expert verified
Slope = 4, y-intercept = -7.
Step by step solution
01
Write the equation in slope-intercept form
The slope-intercept form of a line is given by the equation \( y = mx + b \), where \(m\) is the slope and \(b\) is the y-intercept.Start by rearranging the equation \(4x - y = 7\) to solve for \(y\).
02
Solve for y
Subtract \(4x\) from both sides to isolate \(y\):\[ -y = -4x + 7 \]Next, multiply both sides by -1 to solve for \(y\):\[ y = 4x - 7 \]Now, the equation is in the slope-intercept form \(y = mx + b\).
03
Identify the slope and y-intercept
In the equation \( y = 4x - 7 \), the coefficient of \(x\) gives the slope (\(m\)), and the constant term gives the y-intercept (\(b\)).So, the slope is \( m = 4 \), and the y-intercept is \( b = -7 \).
04
Graph the equation
To graph the equation, start by plotting the y-intercept (0, -7) on the coordinate plane. From this point, use the slope to find another point on the line. The slope \(m = 4\) can be interpreted as 'rise over run,' meaning rise 4 units up and 1 unit to the right. Plot this second point (1, -3). Draw a line through the two points to complete the graph.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
graphing linear equations
Understanding how to graph linear equations is fundamental in algebra. A linear equation is simply an equation that forms a straight line when graphed on a coordinate plane. The standard way to graph these equations is by using the slope-intercept form, which is written as \( y = mx + b \).
Here, \( m \) represents the slope of the line, and \( b \) represents the y-intercept.
To graph a linear equation:
Here, \( m \) represents the slope of the line, and \( b \) represents the y-intercept.
To graph a linear equation:
- First, identify the y-intercept and plot it on the y-axis.
- Then, use the slope to determine the direction of the line.
- Draw a straight line through these points.
finding slope
The slope of a line indicates its steepness and direction. It is represented by the letter \( m \) in the slope-intercept form \( y = mx + b \). The slope is calculated as the 'rise over run', which means the change in the y-coordinates divided by the change in the x-coordinates between two points on the line.
For instance, in our example equation \( y = 4x - 7 \), the slope \( m = 4 \) means that for every unit increase in x, the y value increases by 4 units.
This can be visualized as:
For instance, in our example equation \( y = 4x - 7 \), the slope \( m = 4 \) means that for every unit increase in x, the y value increases by 4 units.
This can be visualized as:
- 'Rise' 4 units up the y-axis.
- 'Run' 1 unit to the right on the x-axis.
y-intercept
The y-intercept is where the line crosses the y-axis. This point is crucial because it gives a fixed starting point on the graph. In the slope-intercept form \( y = mx + b \), the y-intercept is represented by the constant term \( b \).
For our example, the equation \( y = 4x - 7 \) shows that the y-intercept \( b \) is -7. This means the line crosses the y-axis at the point (0, -7).
To summarize:
For our example, the equation \( y = 4x - 7 \) shows that the y-intercept \( b \) is -7. This means the line crosses the y-axis at the point (0, -7).
To summarize:
- Locate the y-intercept, plot it on the coordinate plane exactly on the y-axis.
- Use the slope from this point to find another point on the line.
- Then, draw a line through these points.