Chapter 7: Problem 44
Contains the origin and is parallel to the line \(-2 x-9 y=4\)
Short Answer
Expert verified
The equation is \(y = -\frac{2}{9}x\).
Step by step solution
01
Understand the Given Line Equation
The given line equation is \(-2x - 9y = 4\). Our goal is to find a new line that is parallel to this line and passes through the origin (0,0).
02
Convert the Equation to Slope-Intercept Form
Rearrange the line equation \(-2x - 9y = 4\) to the slope-intercept form \(y = mx + b\), where \(m\) is the slope.Start by subtracting \(-2x\) from both sides: \[-9y = 2x + 4\]Then, divide every term by \(-9\):\[y = -\frac{2}{9}x - \frac{4}{9}\]The slope \(m\) of this line is \(-\frac{2}{9}\).
03
Identify the Slope of the Parallel Line
Since lines that are parallel share the same slope, the slope of the new line is also \(-\frac{2}{9}\).
04
Use the Slope to Write the New Line Equation
We know the line is of the form \(y = mx + b\) and passes through the origin (0,0), which means when \(x = 0\), \(y = 0\). Substitute \(m = -\frac{2}{9}\) and the point (0,0) into the equation:\[y = -\frac{2}{9}x + b\]Since it passes through the origin, \(b = 0\), so the equation is:\[y = -\frac{2}{9}x\]
05
Verify the Equation
To verify, check the line equation \(y = -\frac{2}{9}x\) passes through the origin. Substitute \(x = 0\) and check \(y\):\[y = -\frac{2}{9}(0) = 0\]This confirms the line passes through the origin and has the same slope as the original line \(-2x - 9y = 4\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Slope-Intercept Form
The slope-intercept form of a linear equation is a popular and easy-to-use way of expressing lines on a graph. It is written as \(y = mx + b\), where:
- \(m\) represents the slope of the line, which indicates how steep the line is.
- \(b\) is the y-intercept, the point where the line crosses the y-axis.
Linear Equation
A linear equation represents a straight line on a graph and can have different forms, such as slope-intercept form or standard form. The standard form is \(Ax + By = C\), where \(A\), \(B\), and \(C\) are constants. To understand the characteristics of the line, such as its slope and intercepts, the slope-intercept form is often more helpful.
In our exercise, we started with the linear equation \(-2x - 9y = 4\), and converted it to the slope-intercept form to find the slope. This transformation helps us understand the direction and steepness of the line, whether it increases or decreases as you move along the x-axis.
In our exercise, we started with the linear equation \(-2x - 9y = 4\), and converted it to the slope-intercept form to find the slope. This transformation helps us understand the direction and steepness of the line, whether it increases or decreases as you move along the x-axis.
Origin
The origin in a coordinate plane is the point where both the x-axis and y-axis intersect, denoted as \((0,0)\). It is a pivotal reference point, especially when determining the y-intercept of a linear equation.
- Lines that pass through the origin have a y-intercept of 0.
- This makes their equation relatively simpler, since the y-intercept term, \(b\), is unnecessary: \(y = mx\).