2x 3y 12 In Slope Intercept Form

Understanding and Converting 2x + 3y = 12 to Slope-Intercept Form

The equation 2x + 3y = 12 represents a straight line on a coordinate plane. While this form, often called the standard form of a linear equation, is useful in certain contexts, the slope-intercept form, y = mx + b, offers a more intuitive understanding of the line's characteristics: its slope (m) and its y-intercept (b). This article will guide you through the process of converting 2x + 3y = 12 into slope-intercept form, explaining the underlying concepts and providing further insights into the properties of this line. We'll also delve into related topics such as finding the x-intercept, graphing the line, and addressing common questions.

Understanding Slope-Intercept Form (y = mx + b)

Before we begin the conversion, let's refresh our understanding of the slope-intercept form: y = mx + b.

• y: Represents the dependent variable, typically plotted on the vertical axis.
• x: Represents the independent variable, typically plotted on the horizontal axis.
• m: Represents the slope of the line. The slope indicates the steepness and direction of the line. A positive slope indicates an upward trend (from left to right), while a negative slope indicates a downward trend. The slope is calculated as the change in y divided by the change in x (rise over run).
• b: Represents the y-intercept, which is the point where the line intersects the y-axis (where x = 0).

Converting 2x + 3y = 12 to Slope-Intercept Form

The goal is to manipulate the equation 2x + 3y = 12 so that it's in the form y = mx + b. Here's a step-by-step guide:

1. Isolate the term with 'y': Start by subtracting 2x from both sides of the equation:

   2x + 3y - 2x = 12 - 2x

   This simplifies to:

   3y = -2x + 12

2. Solve for 'y': To isolate 'y', divide both sides of the equation by 3:

   3y / 3 = (-2x + 12) / 3

   This simplifies to:

   y = (-2/3)x + 4

Now, we have the equation in slope-intercept form: y = (-2/3)x + 4

Interpreting the Slope and Y-intercept

From the slope-intercept form, y = (-2/3)x + 4, we can directly identify the slope and y-intercept:

• Slope (m) = -2/3: This indicates a negative slope, meaning the line descends from left to right. The slope of -2/3 means that for every 3 units increase in x, y decreases by 2 units.

• Y-intercept (b) = 4: This means the line crosses the y-axis at the point (0, 4).

Finding the X-intercept

The x-intercept is the point where the line intersects the x-axis (where y = 0). To find it, we substitute y = 0 into the original equation or the slope-intercept form:

Using the original equation: 2x + 3(0) = 12 => 2x = 12 => x = 6

Using the slope-intercept form: 0 = (-2/3)x + 4 => (2/3)x = 4 => x = 6

Therefore, the x-intercept is (6, 0).

Graphing the Line

Now that we have the slope, y-intercept, and x-intercept, we can easily graph the line:

1. Plot the y-intercept: Plot the point (0, 4) on the y-axis.
2. Use the slope to find another point: Since the slope is -2/3, from the y-intercept (0, 4), move 3 units to the right and 2 units down. This gives you the point (3, 2). You can also move 3 units to the left and 2 units up to get the point (-3, 6).
3. Draw the line: Draw a straight line through the points (0, 4), (3, 2), and (-3, 6). This line represents the equation 2x + 3y = 12.

Further Understanding: Parallel and Perpendicular Lines

The slope plays a crucial role in determining the relationship between lines.

• Parallel Lines: Lines that are parallel have the same slope. Any line parallel to y = (-2/3)x + 4 will also have a slope of -2/3.

• Perpendicular Lines: Lines that are perpendicular have slopes that are negative reciprocals of each other. The negative reciprocal of -2/3 is 3/2. Any line perpendicular to y = (-2/3)x + 4 will have a slope of 3/2.

Applications of Linear Equations

Linear equations like 2x + 3y = 12 have numerous applications across various fields:

• Physics: Describing the relationship between variables like distance and time, or force and acceleration.
• Economics: Modeling supply and demand curves, or cost and revenue functions.
• Engineering: Calculating slopes and gradients in structural design.
• Computer Science: Representing relationships between data points in algorithms and machine learning.

Frequently Asked Questions (FAQ)

Q1: Why is the slope-intercept form important?

A1: The slope-intercept form (y = mx + b) is crucial because it directly reveals the slope (m) and y-intercept (b) of the line. This makes it easy to understand the line's characteristics, graph it quickly, and analyze its relationship with other lines.

Q2: Can I convert the equation back to standard form?

A2: Yes, absolutely. To convert y = (-2/3)x + 4 back to standard form (Ax + By = C), multiply the entire equation by 3 to eliminate the fraction:

3y = -2x + 12

Then, add 2x to both sides to get:

2x + 3y = 12

This is the original standard form equation.

Q3: What if the equation isn't easily solvable for 'y'?

A3: Some equations might require more complex algebraic manipulations to isolate 'y'. This could involve factoring, using the quadratic formula, or other techniques depending on the complexity of the equation.

Q4: What are some other forms of linear equations?

A4: Besides standard form and slope-intercept form, other common forms include:

• Point-slope form: y - y1 = m(x - x1), where (x1, y1) is a point on the line and m is the slope.
• Two-point form: (y - y1) / (x - x1) = (y2 - y1) / (x2 - x1), where (x1, y1) and (x2, y2) are two points on the line.

Conclusion

Converting the equation 2x + 3y = 12 into slope-intercept form, y = (-2/3)x + 4, provides a clear and concise representation of the line. Understanding the slope (-2/3) and y-intercept (4) allows for easy graphing and analysis of the line's properties, including identifying parallel and perpendicular lines. The slope-intercept form is a fundamental concept in algebra with wide-ranging applications in various fields, making it a crucial skill to master. This detailed explanation and exploration of related concepts aim to provide a thorough understanding of linear equations and their representation. Remember to practice converting equations and graphing lines to solidify your understanding.