WAEC Further Mathematics 2024 Objective — Question 21
Question 21 of 40 from the West African Examinations Council (WAEC) Further Mathematics 2024 Objective paper, with the correct answer and a full explanation.
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21. Find the range of values of x for which 9x - 1 > 14x^2.
- A. 1/7 < x < 1/2Correct
- B. -1/7 < x < 1/2
- C. x <= -1/7 or x >= 1/2
- D. x <= 1/7 or x >= 1/2
Explanation
9x-1>14x^2 => 0>14x^2-9x+1 => 14x^2-9x+1<0 => 7x(2x-1)-1(2x-1)<0 => (2x-1)(7x-1)<0, giving critical points x=1/2 and x=1/7. Testing the intervals shows the expression is negative between the roots, so 1/7 < x < 1/2.
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