Question
Question: If the A.M. of the roots of a quadratic equation is 8/5 and the A.M. of their reciprocals is 8/7, th...
If the A.M. of the roots of a quadratic equation is 8/5 and the A.M. of their reciprocals is 8/7, then the quadratic equation is
A
7x2 + 16x + 5 = 0
B
7x2– 16x + 5 = 0
C
5x2 – 16x + 7 = 0
D
5x2 – 8x + 7 = 0
Answer
5x2 – 16x + 7 = 0
Explanation
Solution
2α+β = 58 ̃ a + b = 16/5 2α1+β1 = 78
̃ a+b/ab=16/7̃ ab =7/5x2–16/5x+7/5=0
̃5x2–16x+7=0