Understanding Exponents and Negative Numbers

Oct 13, 2025 by wbrum.org 73 views

Understanding Exponents and Negative Numbers

When dealing with exponents and negative numbers, it's essential to understand the rules that govern their behavior. In this case, we're given the expression $ (-4)^{-2} \times (-4)^{-3} $, and we need to simplify it. To do this, we'll need to apply the rules of exponents and handle the negative numbers correctly.

The Rules of Exponents

The rules of exponents state that when we multiply two numbers with the same base, we add their exponents. In other words, if we have $ a^m \times a^n $, then the result is $ a^{m+n} $. This rule is known as the product of powers rule.

Applying the Product of Powers Rule

In our expression, we have $ (-4)^{-2} \times (-4)^{-3} $. Since both terms have the same base, $ -4 $, we can apply the product of powers rule. This means that we add the exponents, $ -2 $ and $ -3 $, to get the new exponent.

Simplifying the Expression

Using the product of powers rule, we can simplify the expression as follows:

$ (-4)^{-2} \times (-4)^{-3} = (-4)^{-2-3} = (-4)^{-5} $

Understanding Negative Exponents

Now that we have $ (-4)^{-5} $, we need to understand what a negative exponent means. A negative exponent is equivalent to taking the reciprocal of the base raised to the positive exponent. In other words, $ a^{-n} = \frac{1}{a^n} $.

Simplifying the Negative Exponent

Applying this rule to our expression, we get:

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

Evaluating the Expression

Now that we have the expression in the form of a fraction, we can evaluate it. To do this, we need to calculate the value of $ (-4)^5 $.

Calculating the Value of $ (-4)^5 $

Using the rule of exponents, we know that $ a^n = a \times a \times ... \times a $ (n times). Applying this rule to our expression, we get:

$ (-4)^5 = (-4) \times (-4) \times (-4) \times (-4) \times (-4) $

Evaluating the Product

Now that we have the expression in the form of a product, we can evaluate it. To do this, we need to multiply the numbers together.

$ (-4) \times (-4) \times (-4) \times (-4) \times (-4) = -1024 $

Simplifying the Fraction

Now that we have the value of $ (-4)^5 $, we can simplify the fraction.

$ \frac{1}{(-4)^5} = \frac{1}{-1024} $

Simplifying the Negative Sign

Finally, we need to simplify the negative sign in the denominator. To do this, we can multiply the numerator and denominator by $ -1 $.

$ \frac{1}{-1024} = \frac{-1}{1024} $

Conclusion

In conclusion, we have simplified the expression $ (-4)^{-2} \times (-4)^{-3} $ using the rules of exponents and handling the negative numbers correctly. We applied the product of powers rule to simplify the expression, and then used the rule of negative exponents to evaluate the expression. The final result is $ \frac{-1}{1024} $.

Additional Examples

Here are a few additional examples of simplifying expressions with negative exponents:

$ (-2)^{-3} \times (-2)^{-4} = (-2)^{-3-4} = (-2)^{-7} = \frac{1}{(-2)^7} = \frac{1}{-128} = \frac{-1}{128} $
$ (3)^{-2} \times (3)^{-5} = (3)^{-2-5} = (3)^{-7} = \frac{1}{(3)^7} = \frac{1}{2187} $

Final Thoughts

$Simplifying expressions with negative exponents requires a good understanding of the rules of exponents and how to handle negative numbers. By applying the product of powers rule and the rule of negative exponents, we can simplify complex expressions and arrive at the final result.<br/> **Simplify the Expression: $ (-4)^{-2} \times (-4)^{-3} $ - Q&A**$

Q: What is the rule for multiplying numbers with the same base?

A: The rule for multiplying numbers with the same base is the product of powers rule, which states that if we have $ a^m \times a^n $, then the result is $ a^{m+n} $.

Q: How do we simplify the expression $ (-4)^{-2} \times (-4)^{-3} $?

A: To simplify the expression, we apply the product of powers rule by adding the exponents, $ -2 $ and $ -3 $, to get the new exponent. This gives us $ (-4)^{-2-3} = (-4)^{-5} $.

Q: What does a negative exponent mean?

A: A negative exponent is equivalent to taking the reciprocal of the base raised to the positive exponent. In other words, $ a^{-n} = \frac{1}{a^n} $.

Q: How do we simplify the negative exponent $ (-4)^{-5} $?

A: To simplify the negative exponent, we apply the rule of negative exponents by taking the reciprocal of the base raised to the positive exponent. This gives us $ (-4)^{-5} = \frac{1}{(-4)^5} $.

Q: How do we evaluate the expression $ \frac{1}{(-4)^5} $?

A: To evaluate the expression, we need to calculate the value of $ (-4)^5 $. Using the rule of exponents, we know that $ a^n = a \times a \times ... \times a $ (n times). Applying this rule to our expression, we get $ (-4)^5 = (-4) \times (-4) \times (-4) \times (-4) \times (-4) $.

Q: What is the value of $ (-4)^5 $?

A: Evaluating the product, we get $ (-4) \times (-4) \times (-4) \times (-4) \times (-4) = -1024 $.

Q: How do we simplify the fraction $ \frac{1}{(-4)^5} $?

A: Now that we have the value of $ (-4)^5 $, we can simplify the fraction. We get $ \frac{1}{(-4)^5} = \frac{1}{-1024} $.

Q: How do we simplify the negative sign in the denominator?

A: Finally, we need to simplify the negative sign in the denominator. To do this, we can multiply the numerator and denominator by $ -1 $. This gives us $ \frac{1}{-1024} = \frac{-1}{1024} $.

Q: What is the final result of the expression $ (-4)^{-2} \times (-4)^{-3} $?

A: The final result of the expression is $ \frac{-1}{1024} $.

Q: Can you provide more examples of simplifying expressions with negative exponents?

A: Here are a few additional examples:

$ (-2)^{-3} \times (-2)^{-4} = (-2)^{-3-4} = (-2)^{-7} = \frac{1}{(-2)^7} = \frac{1}{-128} = \frac{-1}{128} $
$ (3)^{-2} \times (3)^{-5} = (3)^{-2-5} = (3)^{-7} = \frac{1}{(3)^7} = \frac{1}{2187} $

Q: What are some common mistakes to avoid when simplifying expressions with negative exponents?

A: Some common mistakes to avoid when simplifying expressions with negative exponents include:

Not applying the product of powers rule correctly
Not understanding the rule of negative exponents
Not simplifying the negative sign in the denominator
Not evaluating the expression correctly

Q: How can I practice simplifying expressions with negative exponents?

A: You can practice simplifying expressions with negative exponents by working through examples and exercises. You can also try creating your own examples and simplifying them to test your understanding.