Chapter 2: Problem 33
Write an equation in slope-intercept form for the line that satisfies each set of conditions. \(x\) -intercept \(-4, y\) -intercept 4
Short Answer
Expert verified
The equation is \( y = x + 4 \).
Step by step solution
01
Understand the Slope-Intercept Form
The slope-intercept form of a line is given by the equation \(y = mx + b\), where \(m\) is the slope of the line and \(b\) is the y-intercept. We need to find values for both \(m\) and \(b\) for the line in question.
02
Identify the y-intercept
The problem states that the y-intercept is 4. This means the equation can start as \(y = mx + 4\). Here, \(b = 4\).
03
Use the x-intercept to find the slope
The x-intercept is given as -4. At the x-intercept, the value of \(y\) is 0, so we can use it to find the slope by substituting into the equation. Substitute \(x = -4\) and \(y = 0\) into \(y = mx + 4\): \[ 0 = m(-4) + 4 \] This simplifies to: \[ -4m = -4 \] Solve for \(m\) to get \(m = 1\).
04
Write the Final Equation
Now that we have the slope \(m = 1\) and the y-intercept \(b = 4\), we can write the equation of the line in slope-intercept form: \[ y = 1x + 4 \] This simplifies further to \( y = x + 4 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding x-intercept
The x-intercept of a line is the point where the line crosses the x-axis. This point has a characteristic feature: the y-value is always zero at the x-intercept. For a given line, knowing the x-intercept is extremely useful for writing equations of the line, especially in the slope-intercept form. In our example, the x-intercept is \(-4\), meaning the line crosses the x-axis at this point.
This tells us that when plotting the graph of the line, the line will intersect the x-axis at the point \((-4, 0)\).
This tells us that when plotting the graph of the line, the line will intersect the x-axis at the point \((-4, 0)\).
- This information can be directly used to determine other features of the line, such as the slope.
- It helps in establishing that for x-intercept, \(y = 0\).
Exploring y-intercept
The y-intercept is equally crucial as the x-intercept when working with linear equations. The y-intercept of a line is where the line crosses the y-axis. At this point, the x-value is zero. In the context of slope-intercept form \(y = mx + b\), the y-intercept is denoted by \(b\).
- For our particular problem, the y-intercept is given as \(4\), meaning the line crosses the y-axis at \((0, 4)\).
- This value directly tells us the constant in our linear equation, indicating the starting point of the line when plotting a graph.
Demystifying Slope
The slope of a line is a measure of how steep or flat the line is. It's expressed as the ratio of the rise (change in y) over the run (change in x). In slope-intercept form, it is represented with \(m\). It's crucial because it depicts the direction and angle of the line.
In our example, after using the given x-intercept and y-intercept, we calculated the slope as \(1\). This means the line rises up one unit for every unit it moves to the right.
In our example, after using the given x-intercept and y-intercept, we calculated the slope as \(1\). This means the line rises up one unit for every unit it moves to the right.
- A slope of \(1\) indicates a line at a \(45^{\circ}\) angle in a standard coordinate system.
- The slope also determines if a line is increasing or decreasing.
Linear Equations and Slope-Intercept Form
Linear equations are foundational in mathematics, describing lines in a two-dimensional space. The slope-intercept form is \(y = mx + b\), where \(m\) represents the slope and \(b\) stands for the y-intercept. This form is advantageous as it quickly tells us about the line's slope and where it crosses the y-axis.
In our task, the line's equation was simplified to \(y = x + 4\).
This means:
In our task, the line's equation was simplified to \(y = x + 4\).
This means:
- The slope \(m\) is \(1\), indicating a steady, 1 to 1 change between x and y.
- The y-intercept \(b\) is \(4\), marking the starting height of the line on the y-axis.