Chapter 4: Problem 35
Write the equation in slope-intercept form. Then graph the equation. $$ 3 x-6 y=9 $$
Short Answer
Expert verified
The equation in slope-intercept form is \(y = \frac{1}{2}x - \frac{3}{2}\), and the line should cross the y-axis at -3/2 and have a slope of 1/2.
Step by step solution
01
Transpose the equation to slope-intercept form
The first step involves getting the equation into slope-intercept form (\(y = mx + b\)). To convert the equation \(3x - 6y = 9\) into slope-intercept form, isolate \(y\). First, divide all terms by 6 to get \(\frac{1}{2}x - y = \frac{3}{2}\). Then bring -\(y\) to the other side to get \(y = \frac{1}{2}x - \frac{3}{2}\).
02
Identify the slope and y-intercept
Now that the equation is in slope-intercept form, it's easy to identify the slope, \(m\), and the y-intercept, \(b\). In the equation \(y = \frac{1}{2}x - \frac{3}{2}\), the slope \(m = \frac{1}{2}\) and the y-intercept \(b = -\frac{3}{2}\).
03
Graph the equation
To graph the equation, start by having the y-intercept as the starting point in your drawing. In this case, the y-intercept is -3/2, so the line will cross the y-axis at -3/2. Then, use the slope to find the next point. The slope is 1/2, which can be understood as 'rise over run', meaning for each unit up (rise) along the y-axis, move 2 units right (run) along the x-axis. After these steps, draw a straight line that passes through these two points and this will be the graph of the equation!
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing Equations
When it comes to graphing equations, especially in slope-intercept form, you're essentially drawing the visual path that an equation takes across a coordinate plane. This type of graphically showing an equation provides a clear picture of how the dependent and independent variables relate to each other.
To begin graphing any equation in slope-intercept form, identify two crucial components from the equation: the slope and the y-intercept. These two elements are like the instructions for your graph.
To begin graphing any equation in slope-intercept form, identify two crucial components from the equation: the slope and the y-intercept. These two elements are like the instructions for your graph.
- Start by plotting the y-intercept on the y-axis. This point marks where the line will cross this vertical axis.
- Then utilize the slope to navigate and find the next point. The slope gives a directional guide, using 'rise over run', to determine the trajectory from one point to the next.
- With these two points plotted, simply connect them with a straight line and extend it across your coordinate plane. This represents the graph of your equation.
Slope
The slope of a line is a measure of its steepness and direction as it travels across the plane. In mathematical terms, the slope is crucial because it quantifies how much a line inclines from the horizontal.
When working with linear equations like the slope-intercept form, the slope is denoted as \(m\) and appears as the coefficient of the \(x\)-term. Understanding the concept of slope involves recognizing:
When working with linear equations like the slope-intercept form, the slope is denoted as \(m\) and appears as the coefficient of the \(x\)-term. Understanding the concept of slope involves recognizing:
- The slope value is a ratio known as 'rise over run', which means how much the line rises vertically for each unit it runs horizontally.
- If the slope is positive, the line ascends as it moves from left to right. Conversely, a negative slope means the line descends.
- A slope of zero indicates a perfectly horizontal line, while undefined or vertical lines do not have numerical slopes.
Y-Intercept
The y-intercept plays an integral role in graphing linear equations. This point indicates where the line crosses the y-axis and provides a starting location for drawing the line.
In any equation structured in slope-intercept form, \(y = mx + b\), the y-intercept is represented by \(b\). It's a stand-alone term, unaffected by \(x\), and serves as a pivotal anchor for your line.
In any equation structured in slope-intercept form, \(y = mx + b\), the y-intercept is represented by \(b\). It's a stand-alone term, unaffected by \(x\), and serves as a pivotal anchor for your line.
- The y-intercept corresponds to the value of \(y\) when \(x\) equals zero, essentially slicing through the y-axis.
- Getting this initial plot on the graph ensures that you have a fixed point to guide where your slope will take you next.
- By establishing the y-intercept first, you simplify the graphing process, making it easier to visualize and establish the line's path.