Let * be an operation on Q − {1} defined by a * b = a + b − ab. The inverse of element 2 is:
Let * be an operation on Q − {1} defined by a * b = a + b − ab. The inverse of element 2 is:
- A. −2
- B. 2
- C. 1/2
- D. −1/2
Answer: B) 2
Explanation: First find identity e: a + e − ae = a → e(1 − a) = 0 → e = 0. Let x be the inverse of 2: 2 * x = 0 → 2 + x − 2x = 0 → 2 − x = 0 → x = 2.
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