NECO Mathematics 2007 Objective — Question 8
Question 8 of 60 from the National Examinations Council (NECO) Mathematics 2007 Objective paper, with the correct answer and a full explanation.
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Rationalise (15+sqrt5)/(4+sqrt5).
- A. 5-sqrt5Correct
- B. 4-sqrt5
- C. 3-sqrt5
Explanation
Multiply numerator and denominator by the conjugate (4-sqrt5): numerator = 55-11sqrt5, denominator = 16-5 = 11, giving (55-11sqrt5)/11 = 5-sqrt5.
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