Chapter 2: Problem 80
Find the slope and the \(y\) -intercept of the line with equation \(2 x-9 y+1=0\)
Short Answer
Expert verified
Slope: \( \frac{2}{9} \). Y-intercept: \( \frac{1}{9} \).
Step by step solution
01
Rearrange the equation into slope-intercept form
The slope-intercept form of a linear equation is \( y = mx + b \), where \( m \) is the slope and \( b \) is the y-intercept. Start by isolating \( y \) on one side of the equation.Given equation: \[ 2x - 9y + 1 = 0 \]Subtract \( 2x \) and \( 1 \) from both sides to isolate \( -9y \):\[ -9y = -2x - 1 \]
02
Solve for y
Divide every term by \( -9 \) to solve for \( y \):\[ y = \frac{2}{9} x + \frac{1}{9} \]Now the equation is in slope-intercept form, \( y = mx + b \).
03
Identify the slope and y-intercept
From the slope-intercept form of the equation \( y = \frac{2}{9} x + \frac{1}{9} \), identify the slope \( m \) and the y-intercept \( b \):Slope \( m = \frac{2}{9} \)Y-intercept \( b = \frac{1}{9} \)
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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 is a commonly used way to express linear equations. The standard form is \ \( y = mx + b \ \). In this equation, \( m \ \) represents the slope of the line, and \( b \ \) represents the y-intercept. This form is very useful because it provides a clear and straightforward way to identify both the slope and the y-intercept directly from the equation.
When working with linear equations, converting them to slope-intercept form can make many tasks, such as graphing, much simpler.
You just need to isolate \( y \ \) on one side of the equation, as shown in the solution above.
When working with linear equations, converting them to slope-intercept form can make many tasks, such as graphing, much simpler.
You just need to isolate \( y \ \) on one side of the equation, as shown in the solution above.
linear equation
A linear equation is an equation that represents a straight line when graphed on a coordinate plane. These equations can be written in several forms, including slope-intercept form, standard form, and point-slope form.
In any linear equation, each term is either a constant or the product of a constant and a single variable. The general form of a linear equation is \( Ax + By + C = 0 \ \), where \( A \ \), \( B \ \), and \( C \ \) are constants.
As demonstrated in the example problem, you can rearrange a linear equation to isolate \( y \ \) and rewrite it in slope-intercept form. This makes it easy to identify the slope and y-intercept.
In any linear equation, each term is either a constant or the product of a constant and a single variable. The general form of a linear equation is \( Ax + By + C = 0 \ \), where \( A \ \), \( B \ \), and \( C \ \) are constants.
As demonstrated in the example problem, you can rearrange a linear equation to isolate \( y \ \) and rewrite it in slope-intercept form. This makes it easy to identify the slope and y-intercept.
rearranging equations
Rearranging equations is a key skill in algebra that involves manipulating the equation to isolate a specific variable. This process often requires adding, subtracting, multiplying, or dividing terms on both sides of the equation.
In our example, we needed to rearrange the given equation \( 2x - 9y + 1 = 0 \ \) to isolate \( y \ \). We did this by:
In our example, we needed to rearrange the given equation \( 2x - 9y + 1 = 0 \ \) to isolate \( y \ \). We did this by:
- Subtracting \( 2x \ \) and \( 1 \ \) from both sides
- Then, dividing every term by \( -9 \ \) to solve for \( y \ \)
slope
The slope of a line measures its steepness and direction. It is denoted by the variable \( m \ \) in the slope-intercept form \( y = mx + b \ \).
Mathematically, the slope is calculated as the ratio of the change in \( y \ \) (vertical change) to the change in \( x \ \) (horizontal change) between two points on the line, represented as \( m = \frac{\Delta y}{\Delta x} \ \).
In our example, once we rearranged the equation into slope-intercept form, we identified the slope \( m \ \) as \( \frac{2}{9} \ \), which means for every 9 units moved horizontally, the line rises by 2 units.
Mathematically, the slope is calculated as the ratio of the change in \( y \ \) (vertical change) to the change in \( x \ \) (horizontal change) between two points on the line, represented as \( m = \frac{\Delta y}{\Delta x} \ \).
In our example, once we rearranged the equation into slope-intercept form, we identified the slope \( m \ \) as \( \frac{2}{9} \ \), which means for every 9 units moved horizontally, the line rises by 2 units.
y-intercept
The y-intercept of a line is the point where it crosses the y-axis. This is represented by the variable \( b \ \) in the slope-intercept form \( y = mx + b \ \).
The y-intercept occurs when the value of \( x \ \) is 0, so you are left with \( y = b \ \).
In our example, after rearranging the equation into slope-intercept form, the y-intercept \( b \ \) is identified as \( \frac{1}{9} \ \). This means the line crosses the y-axis at the point \( (0, \frac{1}{9}) \ \).
This is crucial for graphing linear equations as it gives a starting point for drawing the line.
The y-intercept occurs when the value of \( x \ \) is 0, so you are left with \( y = b \ \).
In our example, after rearranging the equation into slope-intercept form, the y-intercept \( b \ \) is identified as \( \frac{1}{9} \ \). This means the line crosses the y-axis at the point \( (0, \frac{1}{9}) \ \).
This is crucial for graphing linear equations as it gives a starting point for drawing the line.