Question 91 of 480
Divide: \(a^{3x} - 26a^{2x} + 156a^{x} - 216\) by \(a^{2x} - 24a^{x} + 108\).
- A. ax - 2
- B. ax + 2
- C. ax - 8
- D. ax - 6
Correct Answer:
A
Explanation
To solve the problem of dividing the polynomial \(a^{3x} - 26a^{2x} + 156a^{x} - 216\) by \(a^{2x} - 24a^{x} + 108\), we will use polynomial long division. Let's break this down step-by-step.
### Step 1: Set Up the Division
We are dividing:
\[
\text{Dividend: } a^{3x} - 26a^{2x} + 156a^{x} - 216
\]
by
\[
\text{Divisor: } a^{2x} - 24a^{x} + 108.
\]
### Step 2: Perform Polynomial Long Division
1. **Divide the leading term of the dividend by the leading term of the divisor**:
\[
\frac{a^{3x}}{a^{2x}} = a^{x}.
\]
This means our first term in the quotient is \(a^{x}\).
2. **Multiply the entire divisor by \(a^{x}\)**:
\[
a^{x}(a^{2x} - 24a^{x} + 108) = a^{3x} - 24a^{2x} + 108a^{x}.
\]
3. **Subtract this result from the original dividend**:
\[
(a^{3x} - 26a^{2x} + 156a^{x} - 216) - (a^{3x} - 24a^{2x} + 108a^{x}).
\]
This simplifies to:
\[
-26a^{2x} + 24a^{2x} + 156a^{x} - 108a^{x} - 216 = -2a^{2x} + 48a^{x} - 216.
\]
4. **Now, repeat the process with the new polynomial**:
- Divide the leading term \(-2a^{2x}\) by \(a^{2x}\):
\[
\frac{-2a^{2x}}{a^{2x}} = -2.
\]
So, the next term in the quotient is \(-2\).
5. **Multiply the entire divisor by \(-2\)**:
\[
-2(a^{2x} - 24a^{x} + 108) = -2a^{2x} + 48a^{x} - 216.
\]
6. **Subtract this from the current polynomial**:
\[
(-2a^{2x} + 48a^{x} - 216) - (-2a^{2x} + 48a^{x} - 216) = 0.
\]
### Step 3: Conclusion of Division
Since the remainder is \(0\), we conclude that:
\[
\frac{a^{3x} - 26a^{2x} + 156a^{x} - 216}{a^{2x} - 24a^{x} + 108} = a^{x} - 2.
\]
### Final Answer
Thus, the correct option is:
**A. \(ax - 2\)**.
### Explanation of Other Options
- **B. \(ax + 2\)**: This option suggests that the constant term is positive, which contradicts our result of \(-2\).
- **C. \(ax - 8\)**: This option has an incorrect constant term, as we found the constant term to be \(-2\).
- **D. \(ax - 6\)**: Similar to option C, this option also has an incorrect constant term.
### Revision Summary
- Use polynomial long division to divide polynomials.
- Divide the leading terms to find the first term of the quotient.
- Multiply the divisor by the quotient term and subtract from the dividend.
- Repeat until the remainder is zero or the degree of the remainder is less than the degree of the divisor.
This methodical approach ensures clarity and accuracy in polynomial division.