Chapter 1: Problem 32
Graph each line by hand. Give the \(x\) - and y-intercepts. $$4 x-3 y=9$$
Short Answer
Expert verified
The x-intercept is \(\left(\frac{9}{4}, 0\right)\) and the y-intercept is \((0, -3)\).
Step by step solution
01
Identify the Problem
We are given the linear equation \(4x - 3y = 9\). To graph this line, we need to find both the \(x\)-intercept and the \(y\)-intercept.
02
Find the x-intercept
To find the \(x\)-intercept, set \(y = 0\) in the equation and solve for \(x\):\[4x - 3(0) = 9\]\[4x = 9\]\[x = \frac{9}{4}\]So, the \(x\)-intercept is at \(\left(\frac{9}{4}, 0\right)\).
03
Find the y-intercept
To find the \(y\)-intercept, set \(x = 0\) in the equation and solve for \(y\):\[4(0) - 3y = 9\]\[-3y = 9\]\[y = -3\]Thus, the \(y\)-intercept is at \((0, -3)\).
04
Plot the Intercepts
Use the intercepts \(\left(\frac{9}{4}, 0\right)\) and \((0, -3)\) to plot points on the graph. These two points determine the line.
05
Draw the Line
Draw a straight line through the two intercept points to complete 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.
Understanding x-intercepts
The x-intercept is a critical concept when graphing linear equations. It represents the point where a graph crosses the x-axis. At this point, the value of y is always zero.
- To find the x-intercept, substitute 0 for y in the equation and solve for x. For example, in the equation \(4x - 3y = 9\), if we set \(y = 0\), we get:\[4x = 9\]
- Simplifying yields \(x = \frac{9}{4}\), giving the intercept point as \(\left(\frac{9}{4}, 0\right)\).
- This intercept is often plotted on the graph as it provides an anchor point.
Understanding y-intercepts
Similar to the x-intercept, the y-intercept is where the graph crosses the y-axis, meaning the x value is zero at this point.
- To find the y-intercept, substitute 0 for x in the equation and solve for y. For example, in the equation \(4x - 3y = 9\), substituting \(x = 0\) results in \(-3y = 9\).
- Solving this equation gives \(y = -3\), indicating the intercept at \((0, -3)\).
- This y-intercept is key for graphing because it serves as another crucial reference point.
The character of linear equations
A linear equation is any equation that can be written in the form of \(ax + by = c\), where a, b, and c are constants.
- These equations consistently graph as a straight line when plotted on a coordinate plane.
- The general characteristics of linear equations include a constant rate of change and a graph that doesn't curve or break.
- Every linear equation has at least one solution and can have two intercepts, specifically the x- and y-intercepts.
Mastering graphing techniques for linear equations
Graphing linear equations efficiently is a fundamental skill in mathematics. It involves utilizing a few systematic techniques:
- First, calculate both the x- and y-intercepts – these are the primary steps as they provide key points through which the line will pass.
- Plotting these intercepts on the coordinate plane is crucial because they ease the visualization process.
- Once plotted, simply draw a straight line through these points. Ensure the line extends in both directions to demonstrate that it continues infinitely.
- Also, understanding the slope can help. It represents the steepness of the line, calculated as the change in y over the change in x.