Chapter 10: Problem 1
Draw the graph of each equation. Name any intercepts. $$3 x+4 y=12$$
Short Answer
Expert verified
The graph crosses the x-axis at (4,0) and the y-axis at (0,3).
Step by step solution
01
Convert to Slope-Intercept Form
The given equation is \(3x + 4y = 12\). First, we need to express this equation in the slope-intercept form \(y = mx + c\). Begin by solving for \(y\): \[4y = 12 - 3x\]Now, divide the entire equation by 4:\[y = -\frac{3}{4}x + 3\]This is the slope-intercept form, where the slope \(m\) is \(-\frac{3}{4}\) and the y-intercept \(c\) is 3.
02
Identify Intercepts
To find the intercepts of the graph, start with the y-intercept, which is directly from the slope-intercept form: \(c=3\). So, the y-intercept is at \((0, 3)\). Next, find the x-intercept by setting \(y = 0\) in the original equation:\[3x + 4(0) = 12\]This simplifies to:\[3x = 12\]Thus, \(x = 4\). The x-intercept is \((4, 0)\).
03
Plot the Intercepts and Draw the Line
On a coordinate plane, plot the intercepts: the y-intercept at \((0, 3)\) and the x-intercept at \((4, 0)\). These two points determine a straight line. Use a ruler to connect these intercepts with a straight line. This line represents the graph of the equation \(3x + 4y = 12\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Slope-Intercept Form
To comprehend linear equations, it's crucial to understand the slope-intercept form. This form is represented as \(y = mx + c\), where \(m\) signifies the slope, and \(c\) is the y-intercept. The slope \(m\) indicates the steepness or incline of the line, showcasing how much \(y\) changes with respect to \(x\). A positive slope means the line ascends, while a negative one means it descends. The y-intercept, \(c\), shows where the line crosses the y-axis.
In our exercise, we converted the given equation \(3x + 4y = 12\) into the slope-intercept form \(y = -\frac{3}{4}x + 3\). Here, the slope \(-\frac{3}{4}\) illustrates that for every 4 units increase in \(x\), \(y\) decreases by 3 units. The y-intercept is 3, indicating the line crosses the y-axis at (0, 3). Appreciating this transformation helps identify key elements of the graph with ease.
In our exercise, we converted the given equation \(3x + 4y = 12\) into the slope-intercept form \(y = -\frac{3}{4}x + 3\). Here, the slope \(-\frac{3}{4}\) illustrates that for every 4 units increase in \(x\), \(y\) decreases by 3 units. The y-intercept is 3, indicating the line crosses the y-axis at (0, 3). Appreciating this transformation helps identify key elements of the graph with ease.
Graphing Equations
Graphing equations is a visual method to understand linear functions. It involves plotting points on the coordinate plane that satisfy the equation. The simplest way to graph a linear equation is by using its intercepts. This method is practical because two points are generally enough to draw a line in a 2-dimensional plane.
In this exercise, after converting the equation to slope-intercept form, we identified the intercepts and plotted them. The next step is drawing a line that passes through these points. A ruler comes in handy to ensure the line is straight.
In this exercise, after converting the equation to slope-intercept form, we identified the intercepts and plotted them. The next step is drawing a line that passes through these points. A ruler comes in handy to ensure the line is straight.
- Begin by marking the y-intercept on the y-axis.
- Next, locate the x-intercept on the x-axis.
- Finally, draw a straight line through these points to complete the graph.
Intercepts
Intercepts provide crucial insights into linear equations and their graphical representation. An intercept is a point where the line crosses an axis. Each linear equation has potential x-intercept(s) and y-intercept(s), unless the line is parallel to the respective axis.
For the given equation, we determined two intercepts:
For the given equation, we determined two intercepts:
- The y-intercept was found by setting \(x = 0\) in the equation \(y = -\frac{3}{4}x + 3\), yielding the point (0, 3). This shows where the line cuts the y-axis.
- To find the x-intercept, we set \(y = 0\). By solving \(3x + 4(0) = 12\), we derived the point (4, 0). Hence, the line crosses the x-axis here.