Question 267 of 480
What is the result of simplifying the expression \( (2^3 \times 2^{-5}) \) and expressing it in standard form?
- \( 0.125 \)
- \( 0.5 \)
- \( 0.25 \)
- \( 1 \)
Correct Answer:
A
Explanation
To simplify the expression \( (2^3 \times 2^{-5}) \) and express it in standard form, let's break it down step-by-step.
### Step 1: Understanding Exponents
When multiplying numbers with the same base, you can add their exponents. This is a fundamental property of exponents, which states:
\[
a^m \times a^n = a^{m+n}
\]
In our case, the base is \( 2 \), and we have:
\[
2^3 \times 2^{-5}
\]
### Step 2: Applying the Exponent Rule
Now, we can apply the exponent rule:
\[
2^3 \times 2^{-5} = 2^{3 + (-5)} = 2^{3 - 5} = 2^{-2}
\]
### Step 3: Converting to Standard Form
Next, we need to express \( 2^{-2} \) in standard form. The negative exponent indicates that we should take the reciprocal of the base raised to the positive exponent:
\[
2^{-2} = \frac{1}{2^2}
\]
Calculating \( 2^2 \):
\[
2^2 = 4
\]
Thus, we have:
\[
2^{-2} = \frac{1}{4}
\]
### Step 4: Expressing in Decimal Form
To express \( \frac{1}{4} \) in decimal form, we can perform the division:
\[
\frac{1}{4} = 0.25
\]
### Conclusion: Final Answer
The simplified expression \( (2^3 \times 2^{-5}) \) in standard form is \( 0.25 \). Therefore, the correct option is:
**C. \( 0.25 \)**
### Explanation of Other Options
- **A. \( 0.125 \)**: This value corresponds to \( \frac{1}{8} \), which is not the result of our simplification.
- **B. \( 0.5 \)**: This value corresponds to \( \frac{1}{2} \), which is also not the result of our simplification.
- **D. \( 1 \)**: This value corresponds to \( 2^0 \), which is not applicable here since we have a negative exponent.
### Revision Summary
- When multiplying powers with the same base, add the exponents.
- A negative exponent indicates the reciprocal of the base raised to the positive exponent.
- \( 2^{-2} \) simplifies to \( \frac{1}{4} \), which is \( 0.25 \) in decimal form.
- The correct answer is \( 0.25 \) (Option C).