Use the Remainder Theorem quickly Find the remainder when f(x) = x^4 − 6x^3 + 2x^2 + 3x + 1 is divided by (x − 2).
Aptitude
Elementary Algebra
Difficulty: Easy
Choose an option
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A-12
-
B12
-
C17
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D-17
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E-5
Answer
Correct Answer: -17
Explanation
Introduction / Context:The Remainder Theorem states that the remainder when a polynomial f(x) is divided by (x − a) equals f(a). This gives a fast, error-resistant method.
Given Data / Assumptions:
- f(x) = x^4 − 6x^3 + 2x^2 + 3x + 1.
- Divisor is (x − 2), so a = 2.
Concept / Approach:Compute f(2) directly and that value is the remainder.
Step-by-Step Solution:f(2) = 2^4 − 6·2^3 + 2·2^2 + 3·2 + 1.= 16 − 6·8 + 2·4 + 6 + 1.= 16 − 48 + 8 + 6 + 1 = −17.
Verification / Alternative check:Synthetic division at 2 also yields remainder −17.
Why Other Options Are Wrong:12, 17, −12, −5 arise from partial sums or sign slips; only −17 equals f(2).
Common Pitfalls:Forgetting order of operations; miscomputing 6·2^3 as 12 or 48 incorrectly.
Final Answer:−17