Further MathematicsSets, binary operations and logicWAEC
The operation ∘ is defined on the real numbers by a ∘ b = 2a + b − 3. Find (4 ∘ 5) − (5 ∘ 4).
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Answer: B. −1
4 ∘ 5 = 8 + 5 − 3 = 10 and 5 ∘ 4 = 10 + 4 − 3 = 11, so the difference is −1; the operation is not commutative.
An AdmitMe practice question, written for the WAEC syllabus. Not an official past question.