Chapter 7: Problem 6
Graph each equation using the slope and \(y\) -intercept. $$x-2 y=4$$
Short Answer
Expert verified
Graph the line through points (0, -2) and (2, -1) after rewriting as \(y = \frac{1}{2}x - 2\).
Step by step solution
01
Rewrite the Equation in Slope-Intercept Form
The slope-intercept form of an equation is \(y = mx + b\), where \(m\) is the slope and \(b\) is the y-intercept. Start with the equation \(x - 2y = 4\). To rewrite it in slope-intercept form, solve for \(y\) by isolating it on one side of the equation. Subtract \(x\) from both sides:\[-2y = -x + 4\] Next, divide every term by -2:\[y = \frac{1}{2}x - 2\] Now, the equation is in slope-intercept form with \(m = \frac{1}{2}\) and \(b = -2\).
02
Identify the Slope and Y-Intercept
From the equation \(y = \frac{1}{2}x - 2\), we can see the slope \(m\) is \(\frac{1}{2}\) and the y-intercept \(b\) is \(-2\).This means the graph of the line will cross the y-axis at \(-2\) and will rise 1 unit for every 2 units it moves to the right.
03
Plot the Y-Intercept
Start by plotting the y-intercept on the graph. Since \(b = -2\), place a point on the y-axis at \(y = -2\). This is the point \( (0, -2) \).
04
Use the Slope to Find Another Point
Use the slope \(m = \frac{1}{2}\) to find another point on the line. The slope \(\frac{1}{2}\) indicates you rise 1 unit up for every 2 units you move right.Starting at the y-intercept (0, -2), move up 1 unit to \(y = -1\), and 2 units to the right to \(x = 2\), placing a point at (2, -1).
05
Draw the Line
Draw a straight line through the points (0, -2) and (2, -1). Extend the line in both directions and add arrows to indicate it extends infinitely.
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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 visualizing algebraic expressions on a coordinate plane. This is crucial in understanding how mathematical relationships look and function in a 2D space. For linear equations such as \(y = \frac{1}{2}x - 2\), we first need to rewrite them into the slope-intercept form. This form, \(y = mx + b\), allows easy identification of fundamental properties like slope and y-intercept.
- Begin with writing the equation in slope-intercept form by solving for \(y\).
- Identify the slope \(m\) and y-intercept \(b\).
- Plot these points and use the slope to find additional points.
Y-Intercept
The y-intercept is a key element in graphing linear equations; it marks where the line crosses the y-axis. In the equation \(y = mx + b\), \(b\) represents the y-intercept.
For the line described by \(y = \frac{1}{2}x - 2\), the y-intercept is at \(b = -2\). This means the line crosses the y-axis at the point \((0, -2)\).
For the line described by \(y = \frac{1}{2}x - 2\), the y-intercept is at \(b = -2\). This means the line crosses the y-axis at the point \((0, -2)\).
- Simply locate \(y = -2\) on the y-axis.
- Place a point at \((0, -2)\) to set the starting point of your line.
Slope Calculation
Slope calculation is essential for determining a line's steepness and direction. The slope indicates how quickly or slowly a line ascends or descends when moving from left to right.
For the equation \(y = \frac{1}{2}x - 2\), the slope \(m\) is \(\frac{1}{2}\). This tells us:
For the equation \(y = \frac{1}{2}x - 2\), the slope \(m\) is \(\frac{1}{2}\). This tells us:
- The line rises 1 unit for every 2 units it moves to the right.
- A positive slope means the line ascends as it moves from left to right.