Problem 62

Question

a. Rewrite the given equation in slope-intercept form. b. Give the slope and y-intercept. c. Use the slope and y-intercept to graph the linear function. $$4 x+6 y+12=0$$

Step-by-Step Solution

Verified
Answer
The equation in slope-intercept form is \(y = -2/3x - 2\). The slope is -2/3 and the y-intercept is -2. Using these values, we can draw the graph of the equation.
1Step 1: Rewrite the equation in slope-intercept form
Firstly, rearrange the given equation 4x + 6y + 12 = 0 to obtain a form y = mx + b by isolating y. This is done as: \[6y = -4x -12 \]\[y = \frac{-4}{6}x - \frac{12}{6}\] So y = \(-\frac{2}{3}x - 2\).
2Step 2: Identify the slope and y-intercept
In the slope-intercept form of the equation, y = mx + b, the coefficient of x is the slope and the constant term is the y-intercept. Here, m = -2/3 is the slope and b = -2 is the y-intercept.
3Step 3: Graph the linear function
Start by plotting the y-intercept (-2) on the y-axis. The slope is -2/3, which means for every 3 units moved to right on the x-axis, we move 2 units down. Following this pattern, we can plot other points and draw the line.

Key Concepts

Linear Function GraphingSlope of a LineY-Intercept
Linear Function Graphing
Graphing a linear function involves translating the algebraic representation of a line into a visual format on a coordinate system. For instance, if we have an equation like \(4x + 6y + 12 = 0\), our first task is to transform it into slope-intercept form, which is \(y = mx + b\), where \(m\) represents the slope, and \(b\) represents the y-intercept. By doing so, we get \(y = -\frac{2}{3}x - 2\).

To graph this equation, we start by locating the y-intercept on the y-axis, which is the point at which the line crosses the y-axis. In this case, the y-intercept is \(b = -2\). From there, we use the slope, which tells us the steepness and direction of the line. The slope of \(m = -\frac{2}{3}\) guides us to move 3 units horizontally (to the right for positive and to the left for negative) and 2 units vertically (up for positive and down for negative) to find the next point. Repeating this process, we can plot several points and draw a straight line through them, completing the graph.
Slope of a Line
The slope is a measure of how steep a line is, and the direction in which it slants. The formula for slope (\(m\)) when given two points, \((x_1, y_1)\) and \((x_2, y_2)\), is \(m = \frac{y_2 - y_1}{x_2 - x_1}\). In the slope-intercept form of a linear equation, \(y = mx + b\), the slope is represented by \(m\). For the equation \(6y = -4x - 12\), once rearranged to slope-intercept form, \(y = -\frac{2}{3}x - 2\), we can identify the slope as \(-\frac{2}{3}\).

When graphing, the slope tells us how to move from one point on the line to another. A positive slope means the line rises as it moves from left to right, while a negative slope means it falls. In our example, the slope of \(-\frac{2}{3}\) denotes a downward slant from left to right. For every three units we move horizontally, the line moves down two units vertically, showing the 'rise over run' relationship that defines slope.
Y-Intercept
The y-intercept is where a line crosses the y-axis on a graph. It is an important feature because it provides us with a starting point for drawing the line. In the slope-intercept form of a linear equation, \(y = mx + b\), the y-intercept is represented by the constant term \(b\).

Returning to our example equation in slope-intercept form, \(y = -\frac{2}{3}x - 2\), the y-intercept is -2. This means that the line crosses the y-axis at the point (0, -2). When graphing, we always begin by plotting the y-intercept. From there, we use the slope to determine the direction and steepness of the line, which helps in plotting the next points. The y-intercept is especially useful because, regardless of the slope, we have a guaranteed point on the line that we can be certain of and use as a reference when drawing the graph.