Chapter 3: Problem 23
Graph each linear equation. Plot four points for each line. $$y=-2 x+3$$
Short Answer
Expert verified
Plot the points (0,3), (1,1), (2,-1), and (3,-3) and draw a line through them.
Step by step solution
01
Understand the equation
The given equation is a linear equation in the slope-intercept form, which is written as \( y = mx + b \). In this equation, \( m \) represents the slope and \( b \) represents the y-intercept.
02
Determine the slope and y-intercept
In the equation \( y = -2x + 3 \), the slope \( m \) is -2 and the y-intercept \( b \) is 3. This means the line will cross the y-axis at the point (0, 3).
03
Plot the y-intercept
Start by plotting the y-intercept (0, 3) on the graph.
04
Use the slope to find additional points
Since the slope is -2, it means that for every 1 unit increase in x, y decreases by 2 units. Use the slope to plot three more points. Start from (0, 3):- From (0,3), move right 1 unit to (1,3). Then move down 2 units to (1, 1). Plot this point.- From (1, 1), move right 1 unit to (2, 1) and then down 2 units to (2, -1). Plot this point.- From (2, -1), move right 1 unit to (3, -1) and then down 2 units to (3, -3). Plot this point.
05
Draw the line
Draw a straight line through all four points to graph the equation \( y = -2x + 3 \). Ensure the line crosses through each plotted point.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Slope-Intercept Form
The equation given in the exercise is in slope-intercept form. This form of a linear equation is written as \( y = mx + b \).
Here:
Here:
- \(m\) stands for the slope of the line, which indicates its steepness or tilt.
- \(b\) represents the y-intercept, which is the point where the line crosses the y-axis.
- The slope \(m = -2\).
- The y-intercept \(b = 3\).
Plot Points
To graph a linear equation, we need points on the graph to connect them and form a line. In this exercise, we start by plotting the y-intercept. For \( y = -2x + 3 \), the y-intercept is (0, 3).
From this y-intercept, use the slope to find additional points.
Since the slope is -2, this means for every 1 unit increase in \(x\), \(y\) decreases by 2 units.
You start at (0, 3):
From this y-intercept, use the slope to find additional points.
Since the slope is -2, this means for every 1 unit increase in \(x\), \(y\) decreases by 2 units.
You start at (0, 3):
- Move right 1 unit to (1, 3), then down 2 units to (1, 1).
- Move right 1 unit to (2, 1), then down 2 units to (2, -1).
- Move right 1 unit to (3, -1), then down 2 units to (3, -3).
Slope
The slope of a line in the equation \( y = mx + b \) is represented by \(m\). The slope indicates how the value of \(y\) changes as \(x\) changes.
More explicitly:
More explicitly:
- A positive slope means the line rises as it moves from left to right.
- A negative slope means the line falls as it moves from left to right.
- A slope of 0 means the line is horizontal.
- An undefined slope (where the equation is in the form \( x = c \)) means the line is vertical.