Question 274 of 480
What is the result of simplifying \( (2^3 \times 2^2) \div 2^4 \) using the laws of indices?
- \( 2^1 \)
- \( 2^0 \)
- \( 2^{-1} \)
- \( 2^2 \)
Correct Answer:
A
Explanation
To simplify the expression \( (2^3 \times 2^2) \div 2^4 \) using the laws of indices, let's break it down step by step.
### Step 1: Apply the Law of Indices for Multiplication
The first part of the expression is \( 2^3 \times 2^2 \). According to the laws of indices, when you multiply two powers with the same base, you add the exponents. This can be expressed as:
\[
a^m \times a^n = a^{m+n}
\]
In our case:
\[
2^3 \times 2^2 = 2^{3+2} = 2^5
\]
### Step 2: Rewrite the Expression
Now, we can rewrite the original expression using the result from Step 1:
\[
(2^3 \times 2^2) \div 2^4 = 2^5 \div 2^4
\]
### Step 3: Apply the Law of Indices for Division
Next, we need to simplify \( 2^5 \div 2^4 \). According to the laws of indices, when you divide two powers with the same base, you subtract the exponents. This can be expressed as:
\[
\frac{a^m}{a^n} = a^{m-n}
\]
Applying this to our expression:
\[
2^5 \div 2^4 = 2^{5-4} = 2^1
\]
### Final Result
Thus, the simplified result of the expression \( (2^3 \times 2^2) \div 2^4 \) is:
\[
2^1
\]
### Conclusion
The correct option is **A. \( 2^1 \)**.
### Explanation of Other Options
- **B. \( 2^0 \)**: This option is incorrect because \( 2^0 \) equals 1, which is not the result we obtained. The exponent zero indicates that the base is raised to zero, resulting in 1, which does not apply here.
- **C. \( 2^{-1} \)**: This option is also incorrect. \( 2^{-1} \) equals \( \frac{1}{2} \), which is not the result of our simplification. Negative exponents indicate the reciprocal of the base raised to the positive exponent, which does not apply in this case.
- **D. \( 2^2 \)**: This option is incorrect as well. \( 2^2 \) equals 4, which is not the result we calculated. This would imply that we added instead of subtracted the exponents in the division step.
### Revision Summary
- Use the law of indices for multiplication: \( a^m \times a^n = a^{m+n} \).
- Use the law of indices for division: \( \frac{a^m}{a^n} = a^{m-n} \).
- Simplify step-by-step, ensuring to apply the correct operations for multiplication and division of powers.
- The final answer for \( (2^3 \times 2^2) \div 2^4 \) is \( 2^1 \).