Chapter 3: Problem 33
Graph each equation by constructing a table of values and then plotting the points. SEE EXAMPLE 2 . (OBJECTIVE 3) $$y=2 x-1$$
Short Answer
Expert verified
The graph of the equation \(y = 2x - 1\) is a straight line that passes through the points (-2, -5), (-1, -3), (0, -1), (1, 1), and (2, 3).
Step by step solution
01
Determine Some X-Values
To construct the table of values, first, choose some x-values to use. These can be any real numbers, but it's usually most convenient to use simple integers. To start with, let's choose -2, -1, 0, 1, 2.
02
Find Corresponding Y-Values
Plug each of the chosen x-values into the equation \(y = 2x - 1\). This gives the corresponding y-values:\n\nFor \(x = -2\), \(y = 2(-2) - 1 = -5\)\nFor \(x = -1\), \(y = 2(-1) - 1 = -3\)\nFor \(x = 0\), \(y = 2(0) - 1 = -1\)\nFor \(x = 1\), \(y = 2(1) - 1 = 1\)\nFor \(x = 2\), \(y = 2(2) - 1 = 3\)
03
Construct the Table of Values
Based on the x and y values obtained we can construct a table of values which looks like:\n\n\[\begin{array}{|c |c|}\hline\text{x} & \text{y} \\hline\text{-2} & \text{-5} \\text{-1} & \text{-3} \\text{0} & \text{-1} \\text{1} & \text{1} \\text{2} & \text{3} \\hline\end{array}\]
04
Plot the Points and Draw the Line
Plot the points (-2, -5), (-1, -3), (0, -1), (1, 1), and (2, 3) on the graph. Then draw a line passing through all of these points. This is the graph of the equation \(y = 2x - 1\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Table of Values
A table of values is a simple tool that helps you organize the coordinates you want to use when graphing a linear equation. By plugging specific x-values into the equation, you find corresponding y-values. This will result in pairs of numbers, known as ordered pairs, that you can later plot on a graph.
**Creating a Table of Values is Easy:**
**Creating a Table of Values is Easy:**
- Pick a few x-values. Generally, integers such as -2, -1, 0, 1, 2 are handy.
- Substitute these x-values into the linear equation to find the y-values.
- Arrange these x and y pairs in a table for easy reference.
Plotting Points
The next step after constructing a table of values is to plot the points on a graph. Every pair of numbers from your table corresponds to a point on the graph, represented by an ordered pair (x, y). Placing these points accurately helps in drawing the correct graph of the equation.
**Procedure for Plotting Points:**
**Procedure for Plotting Points:**
- Read the ordered pairs from the table of values.
- Start with the x-coordinate: move along the x-axis (horizontal line) to reach the correct position.
- Then, use the y-coordinate: move up or down from this position along the y-axis (vertical line).
- Mark the spot where your movements intersect – that's your point!
Coordinate Plane
A coordinate plane is a two-dimensional surface on which we can graph lines and curves. It's made up of two number lines - the horizontal x-axis and the vertical y-axis. These axes divide the plane into four sections, known as quadrants, and intersect at the origin (0,0).
**Understanding the Coordinate Plane:**
**Understanding the Coordinate Plane:**
- The origin is your starting point for all graphing activities.
- X-coordinates tell you how far to move left or right from the origin.
- Y-coordinates tell you how far to move up or down from the origin.
- Each point on the plane is defined by an (x, y) pair.
Linear Function
A linear function is one of the simplest types of functions you can graph on a coordinate plane. It is represented by equations that look like \( y = mx + b \), where \( m \) and \( b \) are constants. The graph of a linear function is always a straight line.
**Facts about Linear Functions:**
**Facts about Linear Functions:**
- The slope \( m \) affects the steepness and direction of the line.
- The y-intercept \( b \) is where the line crosses the y-axis.
- The equation \( y = 2x - 1 \) is a linear function because it can be rearranged into the form \( y = mx + b \).
- To graph, you only need two points, but plotting more points improves accuracy.
Slope
The slope of a line is a measure of its steepness. In the equation of a linear function \( y = mx + b \), the slope is represented by \( m \). It tells you how much the y-value changes for a given change in the x-value.
**Key Points about Slope:**
**Key Points about Slope:**
- A positive slope means the line rises as it moves from left to right.
- A negative slope means the line falls.
- A slope of zero indicates a horizontal line.
- The slope is calculated as the ratio of change in y to the change in x (\( \Delta y / \Delta x \)).