JAMB Mathematics 2009 Objective — Question 21
Question 21 of 50 from the Joint Admissions and Matriculation Board (JAMB) Mathematics 2009 Objective paper, with the correct answer and a full explanation.
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A binary operation Δ defined on the set of integers is such that m Δ n = m + nm + n for all integers m and n. Find the inverse of -5 under this operation, if the identity element is 0
- A. -5/4
- B. -5/6
- C. 0Correct
- D. 5
Explanation
m delta n = m+nm+n. For the identity element e, we have m delta e = m + e + me = m, giving e+me=0, e(1+m)=0, so the identity element is zero, hence the inverse of -5 under this operation is 0.
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