Chapter 8: Problem 16
For Problems 1-36, graph each linear equation. (Objective 2) $$ y=-2 x $$
Short Answer
Expert verified
The graph is a line through the origin with a slope of -2, passing through points like (0,0) and (1,-2).
Step by step solution
01
Identify the Equation Type
The given equation is a linear equation in the form of \(y = mx + c\). Here, \(m = -2\) and \(c = 0\). This means the equation is in the slope-intercept form \(y = mx + b\), where \(b\) is the y-intercept.
02
Determine the Slope and Y-intercept
The slope of the line is \(-2\) and the y-intercept is \(0\). This means the line will pass through the origin \((0, 0)\) and for every one unit increase in \(x\), \(y\) will decrease by \(2\).
03
Plot the Y-Intercept
Start by plotting the y-intercept point \((0, 0)\) on the graph. This is where the line will cross the y-axis.
04
Use the Slope to Plot Another Point
From the y-intercept \((0, 0)\), use the slope \(-2\). This means you will go down 2 units in the y direction as you move 1 unit to the right in the x direction. This leads to another point \((1, -2)\) which you can plot on the graph.
05
Draw the Line
Draw a straight line through the points \((0, 0)\) and \((1, -2)\). Extend this line across the graph to show the full extent of the equation. Make sure the line is straight and goes through all points determined by the slope \(-2\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing Linear Equations
Graphing linear equations involves visually representing them on a coordinate plane. It's a method that shows the solutions of an equation as a line. For the equation \(y = -2x\), we're observing how changes in \(x\) affect \(y\). The line on a graph represents all combinations of \(x\) and \(y\) that satisfy the equation.
To understand graphing, follow these steps:
To understand graphing, follow these steps:
- Identify the equation's form. Here, it's a straight line since it is linear.
- Determine key features like the slope and y-intercept, which guide you in plotting the graph.
- Plot points using the slope to see where the line will go on the plane.
Slope-Intercept Form
The slope-intercept form is a straightforward way to write linear equations. It's given by \(y = mx + b\), where \(m\) represents the slope and \(b\) is the y-intercept. This form is powerful in simplifying the graphing process.
In our equation \(y = -2x\):
In our equation \(y = -2x\):
- Here, \(m = -2\). This tells us how steep the line is and in which direction it moves as \(x\) changes.
- \(b = 0\), meaning the line crosses the y-axis at the origin.
Plotting Points
Plotting points is an essential step in drawing a line on a graph. It involves determining exact locations on the coordinate plane that the line passes through.
To plot points for the equation \(y = -2x\):
To plot points for the equation \(y = -2x\):
- Start with the y-intercept \((0, 0)\) since this is where the line will intersect the y-axis.
- Using the slope, move 1 unit right (increasing \(x\)) and 2 units down (decreasing \(y\)) to find the next point, \((1, -2)\).
- Repeat this step to plot additional points if needed for accuracy.
Y-Intercept
The y-intercept is a fundamental concept in understanding where a line crosses the y-axis on a graph. It is the value of \(y\) when \(x = 0\).
For the line \(y = -2x\):
For the line \(y = -2x\):
- The y-intercept is \((0, 0)\). This shows that the graph line begins at the origin.