Chapter 1: Problem 8
Change the equation \(2 x+3 y+6=0\) to the form \(y=m x+b\), graph the line, and find the \(y\) -intercept and \(x\) -intercept. \(\Rightarrow\)
Short Answer
Expert verified
Equation in form: \(y = -\frac{2}{3}x - 2\), \(y\)-intercept: (0, -2), \(x\)-intercept: (-3, 0).
Step by step solution
01
Re-arranging the Equation
The equation is given as \(2x + 3y + 6 = 0\). Our goal is to express it in the form \(y = mx + b\). Start by isolating the term with \(y\) on one side. Subtract \(2x\) and \(6\) from both sides to get \(3y = -2x - 6\).
02
Solving for y
Now, divide every term by 3 to solve for \(y\). This gives us \(y = -\frac{2}{3}x - 2\). Now the equation is in the desired slope-intercept form \(y = mx + b\) where \(m = -\frac{2}{3}\) and \(b = -2\).
03
Graphing the Line
To graph the line, you can start by plotting the intercepts. The \(y\)-intercept is \(b = -2\) which means the line crosses the \(y\)-axis at (0, -2). The slope \(m = -\frac{2}{3}\) indicates that for every 3 units you move to the right on the \(x\)-axis, you move 2 units down on the \(y\)-axis.
04
Finding the y-intercept
The \(y\)-intercept is the point where the line crosses the \(y\)-axis. For our equation, this is directly given by \(b = -2\). Thus, the \(y\)-intercept is at the point (0, -2).
05
Finding the x-intercept
To find the \(x\)-intercept, set \(y = 0\) in the equation \(2x + 3y + 6 = 0\). Solving for \(x\) gives \(2x + 6 = 0\) or \(2x = -6\). Dividing both sides by 2, we find \(x = -3\). Therefore, the \(x\)-intercept is at the point (-3, 0).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Slope-Intercept Form
Linear equations can often be expressed in different forms to highlight useful properties. One of these forms is the slope-intercept form, which looks like this: \( y = mx + b \). Here, \( m \) represents the **slope** of the line, and \( b \) is the **y-intercept**.
This form is particularly useful because it instantly tells you how steep the line is and where it crosses the y-axis. It makes graphing much easier too! In our original equation \( 2x + 3y + 6 = 0 \), the first step was to rearrange it to look like \( y = mx + b \). This gives us a clearer picture of the line's behavior on a graph.
This form is particularly useful because it instantly tells you how steep the line is and where it crosses the y-axis. It makes graphing much easier too! In our original equation \( 2x + 3y + 6 = 0 \), the first step was to rearrange it to look like \( y = mx + b \). This gives us a clearer picture of the line's behavior on a graph.
Graph of a Line
Graphing a line from its equation gives a visual representation of all solutions to the equation. When the equation is in slope-intercept form, \( y = mx + b \), graphing is fairly straightforward.
To graph our line, we identified the y-intercept \( b = -2 \), meaning the line passes through the point (0, -2) on the y-axis. Additionally, the slope \( m = -\frac{2}{3} \) indicates the line's slant.
To plot the line,:
To graph our line, we identified the y-intercept \( b = -2 \), meaning the line passes through the point (0, -2) on the y-axis. Additionally, the slope \( m = -\frac{2}{3} \) indicates the line's slant.
To plot the line,:
- Start at the y-intercept (0, -2).
- Use the slope: move 3 units to the right and 2 units down to find a second point.
- Draw a line through these points.
Y-Intercept
The y-intercept is an essential characteristic of a line. This is where the line crosses the y-axis, and it's always at the point (0, b).
For our equation, once it was placed into slope-intercept form as \( y = -\frac{2}{3}x - 2 \), it was simple to pinpoint the y-intercept. Here, \( b = -2 \), telling us the line crosses the y-axis at the point (0, -2).
This direct reading of the intercept from the equation makes calculations straightforward, allowing us to graph the point on a graph quickly.
For our equation, once it was placed into slope-intercept form as \( y = -\frac{2}{3}x - 2 \), it was simple to pinpoint the y-intercept. Here, \( b = -2 \), telling us the line crosses the y-axis at the point (0, -2).
This direct reading of the intercept from the equation makes calculations straightforward, allowing us to graph the point on a graph quickly.
X-Intercept
The x-intercept is where the line crosses the x-axis. To find this point, set \( y = 0 \) and solve the equation for \( x \).
In our case, from the original equation \( 2x + 3y + 6 = 0 \), setting \( y = 0 \) resulted in \( 2x + 6 = 0 \). Solving this gives \( x = -3 \), indicating the line crosses the x-axis at the point (-3, 0).
Understanding both x- and y-intercepts enhances graphing, ensuring accuracy for visualizing linear equations.
In our case, from the original equation \( 2x + 3y + 6 = 0 \), setting \( y = 0 \) resulted in \( 2x + 6 = 0 \). Solving this gives \( x = -3 \), indicating the line crosses the x-axis at the point (-3, 0).
Understanding both x- and y-intercepts enhances graphing, ensuring accuracy for visualizing linear equations.