WAEC Mathematics 2017 Theory — Question 22
Question 22 of 25 from the West African Examinations Council (WAEC) Mathematics 2017 Theory paper, with the correct answer and a full explanation.
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12(a) Using the completing the square method, solve, correct to 2 decimal places, the equation 3y^2-5y+2=0
Model answer
Divide through by 3: y^2-(5/3)y+2/3=0 → y^2-(5/3)y=-2/3. Complete the square: [y-(5/6)]^2 = -2/3+(5/6)^2 = -2/3+25/36 = (-24+25)/36 = 1/36. Taking square roots: y-5/6=±1/6. So y=5/6+1/6=1.00 or y=5/6-1/6=4/6=0.67 (2 d.p.).
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