Question

31. The condition that one of ax²+bx+c=0 the roots of is twice the other is
(a) b²=4ca (b) 2b =9 (c+a) (C) 2b²=9ca (d) 2b²=9(c-d)​

Answer 1

Answer:

( A)

Step-by-step explanation:

We have the following quadratic equation-

ax²+bx+c such that α, 2α are the roots

so, sum of the roots = -b/a = 3α

⇒ α = -b/3a  .......(1)

Products of the roots = c/a = 2α²

Put the value of α from equation (1)

⇒ c/a = 2(-b/3a)²

⇒ c/a = 2b²/9a²

⇒ 2b² = 9ac   Answer 

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