The Rule for Dividing Variables with Exponents

Oct 13, 2025 by wbrum.org 45 views

Introduction

When dealing with fractions that contain variables with exponents, it's essential to understand the rules of exponentiation to simplify them. In this case, we're given the expression $\frac{y^{-2}}{y^{-3}}$ , and we need to simplify it by writing the answer with a positive exponent only. This requires us to apply the rules of exponentiation, specifically the rule for dividing variables with exponents.

Understanding Exponents

Before we dive into simplifying the expression, let's quickly review what exponents are and how they work. An exponent is a small number that is written above and to the right of a variable or a number. It tells us how many times to multiply the variable or number by itself. For example, $y^3$ means $y$ multiplied by itself three times: $y \cdot y \cdot y$ .

The Rule for Dividing Variables with Exponents

When we divide two variables with exponents, we subtract the exponents. This is a fundamental rule in algebra that helps us simplify expressions with variables and exponents. The rule is as follows:

\frac{a^m}{a^n} = a^{m-n}

where $a$ is the variable, $m$ and $n$ are the exponents, and $a^{m-n}$ is the result of subtracting the exponents.

Applying the Rule to the Expression

Now that we've reviewed the rule for dividing variables with exponents, let's apply it to the expression $\frac{y^{-2}}{y^{-3}}$ . We can see that both the numerator and the denominator contain the variable $y$ with a negative exponent. To simplify the expression, we'll subtract the exponents:

\frac{y^{-2}}{y^{-3}} = y^{-2-(-3)}

Simplifying the Expression

Now that we've applied the rule, let's simplify the expression further. When we subtract a negative number, it's equivalent to adding a positive number. So, $-2-(-3)$ is equivalent to $-2+3$ , which equals $1$ . Therefore, the expression simplifies to:

y^{-2-(-3)} = y^1

Writing the Answer with a Positive Exponent

As required, we need to write the answer with a positive exponent only. Since $y^1$ is already in the form of a positive exponent, our final answer is:

y^1

Conclusion

In this article, we simplified the expression $\frac{y^{-2}}{y^{-3}}$ by applying the rule for dividing variables with exponents. We subtracted the exponents and simplified the expression to obtain the final answer, $y^1$ . This demonstrates the importance of understanding the rules of exponentiation and how to apply them to simplify expressions with variables and exponents.

Additional Examples

To further illustrate the concept, let's consider a few more examples:

$\frac{y^2}{y^3} = y^{2-3} = y^{-1}$
$\frac{y^{-4}}{y^{-2}} = y^{-4-(-2)} = y^{-2}$
$\frac{y^5}{y^2} = y^{5-2} = y^3$

These examples demonstrate how to apply the rule for dividing variables with exponents to simplify expressions with variables and exponents.

Final Thoughts

Simplifying expressions with variables and exponents requires a solid understanding of the rules of exponentiation. By applying the rule for dividing variables with exponents, we can simplify expressions and write the answer with a positive exponent only. This is an essential skill in algebra and is used extensively in various mathematical applications.

Introduction

In our previous article, we simplified the expression $\frac{y^{-2}}{y^{-3}}$ by applying the rule for dividing variables with exponents. We subtracted the exponents and simplified the expression to obtain the final answer, $y^1$ . In this article, we'll answer some frequently asked questions (FAQs) related to simplifying expressions with variables and exponents.

Q&A

Q: What is the rule for dividing variables with exponents?

A: The rule for dividing variables with exponents is as follows:

\frac{a^m}{a^n} = a^{m-n}

where $a$ is the variable, $m$ and $n$ are the exponents, and $a^{m-n}$ is the result of subtracting the exponents.

Q: How do I simplify an expression with variables and exponents?

A: To simplify an expression with variables and exponents, you need to apply the rule for dividing variables with exponents. If the expression is in the form $\frac{a^m}{a^n}$ , you can subtract the exponents to simplify it.

Q: What if the exponents are negative?

A: If the exponents are negative, you can still apply the rule for dividing variables with exponents. When subtracting negative numbers, it's equivalent to adding positive numbers. So, $-2-(-3)$ is equivalent to $-2+3$ , which equals $1$ .

Q: Can I simplify an expression with variables and exponents if the variables are different?

A: Yes, you can simplify an expression with variables and exponents even if the variables are different. However, you need to apply the rule for dividing variables with exponents separately for each variable.

Q: How do I write the answer with a positive exponent only?

A: To write the answer with a positive exponent only, you need to simplify the expression to obtain a positive exponent. If the exponent is negative, you can multiply the variable by itself to obtain a positive exponent.

Q: What if I have an expression with multiple variables and exponents?

A: If you have an expression with multiple variables and exponents, you can simplify it by applying the rule for dividing variables with exponents separately for each variable.

Examples

Let's consider a few examples to illustrate the concept:

$\frac{y^2}{y^3} = y^{2-3} = y^{-1}$
$\frac{y^{-4}}{y^{-2}} = y^{-4-(-2)} = y^{-2}$
$\frac{y^5}{y^2} = y^{5-2} = y^3$

These examples demonstrate how to apply the rule for dividing variables with exponents to simplify expressions with variables and exponents.

Conclusion

Additional Resources

If you're looking for more resources to help you understand and simplify expressions with variables and exponents, here are a few suggestions:

Khan Academy: Exponents and Exponential Functions
Mathway: Exponents and Exponential Functions
Wolfram Alpha: Exponents and Exponential Functions

These resources provide a comprehensive overview of exponents and exponential functions, including examples, exercises, and interactive tools to help you practice and reinforce your understanding.

Final Thoughts

Simplifying expressions with variables and exponents is an essential skill in algebra and is used extensively in various mathematical applications. By applying the rule for dividing variables with exponents, we can simplify expressions and write the answer with a positive exponent only. With practice and patience, you can master this skill and become proficient in simplifying expressions with variables and exponents.