Justification For Step 2 In Solving Linear Equations

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In the realm of mathematics, linear equations form the bedrock of numerous concepts and applications. Solving these equations requires a systematic approach, with each step carefully justified by fundamental principles. This article delves into the intricacies of solving linear equations, focusing on a specific example and elucidating the justification for a crucial step in the solution process.

Deconstructing the Linear Equation

Let's consider the following linear equation:

16 - 5x = 1 - 4x

This equation presents a relationship between the variable 'x' and constant terms. Our objective is to isolate 'x' on one side of the equation to determine its value. To achieve this, we employ a series of algebraic manipulations, each grounded in mathematical principles.

Step-by-Step Solution

The solution process unfolds as follows:

Step 1:

16 - 5x = 1 - 4x

This is our initial equation, the starting point of our endeavor.

Step 2:

-5x = -4x - 15

This step involves a transformation of the equation. The question at hand is: What justifies this transformation?

Step 3:

-x = -15

This step further simplifies the equation, bringing us closer to the solution.

Unveiling the Justification for Step 2

The pivotal question we aim to address is: What is the justification for Step 2 in the solution process?

To unravel this, let's dissect the transformation from Step 1 to Step 2. We observe that the constant term '16' has been eliminated from the left side of the equation. This elimination is achieved by applying the addition property of equality.

The addition property of equality states that adding the same quantity to both sides of an equation preserves the equality. In simpler terms, if we perform the same addition operation on both sides of an equation, the balance remains intact.

In our case, we add '-16' to both sides of the equation in Step 1:

16 - 5x + (-16) = 1 - 4x + (-16)

Simplifying this, we get:

-5x = -4x - 15

This is precisely the equation we have in Step 2. Therefore, the justification for Step 2 is the addition property of equality. By adding '-16' to both sides, we effectively isolate the terms containing 'x' on one side of the equation.

Elaboration on the Addition Property of Equality

The addition property of equality is a cornerstone of algebraic manipulations. It allows us to rearrange equations while maintaining their validity. This property is not limited to adding constants; we can also add terms containing variables to both sides of an equation.

For instance, if we had an equation like:

x + 3 = 5

We could add '-3' to both sides to isolate 'x':

x + 3 + (-3) = 5 + (-3)

This simplifies to:

x = 2

The addition property of equality is a versatile tool in our algebraic arsenal, enabling us to manipulate equations strategically to solve for unknown variables.

Why Not the Multiplication Property of Equality?

The question might arise: Why isn't the multiplication property of equality the justification for Step 2? The multiplication property of equality states that multiplying both sides of an equation by the same non-zero quantity preserves the equality.

While the multiplication property is indeed a valid algebraic principle, it doesn't directly apply in this specific step. In Step 2, we are adding a quantity to both sides of the equation, not multiplying. The multiplication property would come into play if we needed to multiply both sides of the equation by a constant to simplify it further.

For example, if we had an equation like:

2x = 6

We could multiply both sides by '1/2' (or divide by '2') to isolate 'x':

(1/2) * 2x = (1/2) * 6

This simplifies to:

x = 3

In this case, the multiplication property of equality would be the appropriate justification.

Completing the Solution

Having established the justification for Step 2, let's complete the solution process for the linear equation:

Step 2:

-5x = -4x - 15

Step 3:

-x = -15

To get to step 3, we again use the addition property of equality, but this time, we add 4x to both sides of the equation:

-5x + 4x = -4x - 15 + 4x

Which simplifies to:

-x = -15

Step 4:

To isolate 'x', we multiply both sides of the equation by '-1'. This is an application of the multiplication property of equality.

(-1) * (-x) = (-1) * (-15)

This simplifies to:

x = 15

Therefore, the solution to the linear equation is x = 15.

The Significance of Justification

In mathematics, justification is paramount. Each step in a solution process must be logically sound and supported by mathematical principles. This rigor ensures the accuracy and validity of our results.

Understanding the justifications behind each step not only helps us solve equations correctly but also deepens our understanding of the underlying mathematical concepts. It transforms equation-solving from a rote exercise into a meaningful exploration of mathematical relationships.

Conclusion

In summary, the justification for Step 2 in the solution process of the linear equation 16 - 5x = 1 - 4x is the addition property of equality. By adding '-16' to both sides of the equation, we isolate the terms containing 'x' on one side, paving the way for further simplification and ultimately, the solution. This exploration underscores the importance of understanding the fundamental principles that govern algebraic manipulations, empowering us to solve equations with confidence and clarity. The addition property of equality is a fundamental concept in algebra, allowing us to manipulate equations while preserving their balance. It's a key tool for solving linear equations and understanding more complex mathematical relationships. Remember, each step in solving an equation should be justified by a valid mathematical principle, ensuring the accuracy and validity of the solution. Mastering these principles is crucial for success in mathematics and related fields.