Chapter 1: Problem 25
In Exercises 17–30, write an equation for each line described. Has \(y\) -intercept 4 and \(x\) -intercept \(-1\)
Short Answer
Expert verified
The equation is \( y = 4x + 4 \).
Step by step solution
01
Understanding the Problem
We are tasked with writing the equation of a line given its intercepts. The y-intercept is 4 and the x-intercept is -1.
02
Identifying the Form
To find the equation of the line, we can use the slope-intercept form, which is \( y = mx + b \), where \( m \) is the slope and \( b \) is the y-intercept.
03
Applying Intercept Information
Given the intercepts, the points on the line are (0, 4) for the y-intercept and (-1, 0) for the x-intercept. These points can be used to calculate the slope.
04
Calculating the Slope
The slope \( m \) is calculated using the formula \( m = \frac{y_2 - y_1}{x_2 - x_1} \), where \((x_1, y_1) = (0, 4)\) and \((x_2, y_2) = (-1, 0)\). Substituting the values, we get \( m = \frac{0 - 4}{-1 - 0} = \frac{-4}{-1} = 4 \).
05
Writing the Equation in Slope-Intercept Form
Now that we know the slope \( m = 4 \) and the y-intercept \( b = 4 \), we substitute these values into the slope-intercept form: \( y = 4x + 4 \).
06
Verification of Intercepts
To verify, substitute \( x = 0 \) to find \( y \), which gives \( y = 4 \), confirming the y-intercept. For the x-intercept, set \( y = 0 \) and solve \( 0 = 4x + 4 \), resulting in \( x = -1 \), confirming the x-intercept.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Slope-Intercept Form
The slope-intercept form is a way to express the equation of a straight line through its slope and y-intercept. This form is written as \( y = mx + b \), where \( m \) represents the slope, and \( b \) is the y-intercept. It's a straightforward way to understand the general direction and position of a line on a coordinate plane.
The slope \( m \) tells us how steep the line is. A positive slope means the line ascends from left to right, while a negative slope means it descends. The value \( b \), the y-intercept, indicates where the line crosses the y-axis.
Using the slope-intercept form is extremely helpful in quickly graphing lines and understanding their behavior. By simply knowing the slope and y-intercept, you can sketch the graph of the line without needing any other points.
The slope \( m \) tells us how steep the line is. A positive slope means the line ascends from left to right, while a negative slope means it descends. The value \( b \), the y-intercept, indicates where the line crosses the y-axis.
Using the slope-intercept form is extremely helpful in quickly graphing lines and understanding their behavior. By simply knowing the slope and y-intercept, you can sketch the graph of the line without needing any other points.
X-Intercept
The x-intercept of a line is the point where the line crosses the x-axis. This means the y-value at this point is always zero. To find the x-intercept, we set \( y = 0 \) in the line's equation and solve for \( x \).
Understanding the x-intercept is crucial since it provides insight into where the line interacts with the horizontal axis. In practical situations, x-intercepts can represent time, distance, or other variables reaching a baseline value.
In our exercise, the x-intercept is -1. We verified it by plugging \( y = 0 \) into the line equation \( y = 4x + 4 \), resulting in \( x = -1 \). This confirms where the line meets the x-axis.
Understanding the x-intercept is crucial since it provides insight into where the line interacts with the horizontal axis. In practical situations, x-intercepts can represent time, distance, or other variables reaching a baseline value.
In our exercise, the x-intercept is -1. We verified it by plugging \( y = 0 \) into the line equation \( y = 4x + 4 \), resulting in \( x = -1 \). This confirms where the line meets the x-axis.
Y-Intercept
The y-intercept is the point where a line crosses the y-axis. Here, the x-value is always zero. To find the y-intercept in an equation, set \( x = 0 \) and solve for \( y \).
The y-intercept is an important aspect of the line's equation because it provides a starting point on the graph. It represents the value of \( y \) when \( x \) is zero, which can be a critical reference for understanding the behavior of a line.
In our particular case, the y-intercept is 4. By substituting \( x = 0 \) in the line equation, we confirm \( y = 4 \), showing this line intersects the y-axis at 4. It sets a clear point on the graph from which the line's slope will dictate the rise and run.
The y-intercept is an important aspect of the line's equation because it provides a starting point on the graph. It represents the value of \( y \) when \( x \) is zero, which can be a critical reference for understanding the behavior of a line.
In our particular case, the y-intercept is 4. By substituting \( x = 0 \) in the line equation, we confirm \( y = 4 \), showing this line intersects the y-axis at 4. It sets a clear point on the graph from which the line's slope will dictate the rise and run.