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Find the condition on `a , b ,c ,d`such that equations `2a x^2+b^2+c x+d=0a n d2a x 62+3b x+4x=0`have a common root. |
Answer» Let `alpha` be a common root of the given two equations. Thus `2aalpha^(3) + balpha^(2) + calpha + d = 0` (1) `2aalpha^(2) + 3balpha + 4c = 0` (2) Multiplying (2) with `alpha` and then subtracting (1) from it, we get `2balpha^(2) + 3calpha -d = 0` (3) Now, Eqs. (2) and (3) re quadratic having a common root `alpha `, so `(-2ad - 8bc)^(2) = (-3bd - 12c^(2)) (6ac - 6b^(2))` `rArr (ad + 4 bc)^(2) = (9)/(2) (bd + 4c^(2) (b^(2) - ac)` |
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