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The roots of `ax^(2) - bx + 2x = 0` are in the ratio of `2 : 3`, then `"____"`.A. `a^(2) = bc`B. `3b^(2) = 25 ac`C. `2b^(2) = 75 c`D. `5b^(2) = ac` |
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Answer» Correct Answer - B Let `alpha, beta` be the roots of `ax^(2 - bx + 2c = 0` Given `= alpha/beta = 2/3` `rArr = (2beta)/(3)` Product of the roots `(2beta)/(3) x beta = (2c)/(a)` `beta^(2) = (3c)/(a) " "(1)` Sum of the roots `= alpha + beta` `rArr (2beta)/(3) + beta = (b)/(a)` `rArr (5beta)/(3) = b/a` `beta = (3b)/(5a)` `beta^(2) = (9b^(2))/(25a^(2))" "(2)` From Eqs. (1) and (2) `(3c)/(a) = (9b^(2))/(25a^(2)) 3b^(2) = 25 ac`. |
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