Chapter 8: Problem 8
Write an equation of each line with the given slope and containing the given point. Write the equation in the slope-intercept form \(y=m x+b .\) See Example \(1 .\) Slope \(-\frac{1}{5} ;\) through (4,-6)
Short Answer
Expert verified
The equation of the line is \( y = -\frac{1}{5}x - \frac{26}{5} \).
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 \( m \) represents the slope and \( b \) is the y-intercept, which is where the line crosses the y-axis. We need to find both \( m \) and \( b \) to write the equation.
02
Substitute the Slope
We are given a slope of \( -\frac{1}{5} \). Substitute this into the equation \( y = mx + b \) to get \( y = -\frac{1}{5}x + b \). This will help us in finding the y-intercept \( b \).
03
Use the Point to Solve for b
We need to substitute the given point \((4, -6)\) into the equation \( y = -\frac{1}{5}x + b \). Using \( x = 4 \) and \( y = -6 \), we substitute them in:\[ -6 = -\frac{1}{5}(4) + b \]Simplify the equation:\[ -6 = -\frac{4}{5} + b \]
04
Solve for the Y-Intercept (b)
Continuing from the previous step:Add \( \frac{4}{5} \) to both sides of the equation to solve for \( b \):\[ -6 + \frac{4}{5} = b \]Convert \( -6 \) to a fraction: \( -\frac{30}{5} \)\[ -\frac{30}{5} + \frac{4}{5} = b \]\[ b = -\frac{26}{5} \]
05
Write the Final Equation
Now that we have both \( m \) and \( b \), substitute them back into the slope-intercept form \( y = mx + b \):\[ y = -\frac{1}{5}x - \frac{26}{5} \]This is the equation of the line with the given slope that goes through the point \((4, -6)\).
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.
Equation of a Line
The equation of a line is a powerful tool in algebra that represents a straight line on a coordinate plane. In its simplest form, the equation is expressed as \( y = mx + b \). The two main components of this equation are the slope \( m \) and the y-intercept \( b \). Understanding these components can help in visualizing how the line behaves. The slope \( m \) indicates the steepness and direction of the line, while the y-intercept \( b \) shows where the line crosses the y-axis. By knowing these, we can predict and calculate every point along the line. A line’s equation consolidates an infinite number of points into a concise algebraic expression.
Finding Y-Intercept
Finding the y-intercept \( b \) is crucial when writing the equation of a line in slope-intercept form. The y-intercept is the point where the line crosses the y-axis, meaning it occurs at \( x = 0 \). To find \( b \), you begin with substituting the known values into the equation \( y = mx + b \). If the slope \( m \) and a point \((x, y)\) are known, simply rearrange and solve for \( b \).
- Insert the values of the slope and the coordinates into the equation.
- Simplify the resulting expression by solving for \( b \).
Using Given Point for Equations
When given a specific point on the line, such as \((4, -6)\), this information can be used to complete the equation of the line. Inserting the x and y coordinates of the point into the equation \( y = mx + b \) assists in solving for the y-intercept \( b \). The process is straightforward:
- Begin with the equation with the known slope and unknown \( b \), such as \( y = -\frac{1}{5}x + b \).
- Substitute the x-value and y-value from the point into the equation.
- Rearrange the equation to solve for \( b \).
Algebraic Problem Solving
Algebraic problem solving involves using algebraic methods to find unknown values. In this context, solving for \( b \) requires manipulating the equation \( y = mx + b \) to isolate \( b \). This involves combining like terms and adjusting both sides of the equation until you have \( b = \) (some value). For example:
- Follow the arithmetic operations to simplify the expressions.
- Convert whole numbers to fractions if needed, to match denominators.
- Ensure all calculations are properly executed, especially when fractions are involved.