WAEC 2022 Mathematics · Question 41
Given that log 27 = 2x + 1, find the value of x.
Options
- A.0
- B.1
- C.2
- D.3
Answer: B. 1
Explanation written with AI and checked against the answer key
Analyze the question: We are given log₃ 27 = 2x + 1 and need to find x. Concept: A logarithm answers the question "to what power must the base be raised to give this number?" log_b N = p means b^p = N. Solution: Step 1: Evaluate log₃ 27. 27 = 3³, so log₃ 27 = 3. Step 2: Substitute into the equation. 3 = 2x + 1 Step 3: Solve for x. 2x = 3 − 1 = 2 x = 1 Check: 2(1) + 1 = 3, and log₃ 27 = 3. ✓ Answer: x = 1, which is option B. Tip: Always rewrite the number as a power of the base (27 = 3³, 81 = 3⁴, 125 = 5³). Once you do this, the log is just the exponent. Memorize the powers of 2, 3, and 5 up to about 5 or 6, since they appear often in WASSCE, NECO and JAMB.AI can make mistakes. Report anything that looks wrong.
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