If d,e,f are in G.P. and the two quadratic equations ax^2+2bx+c=0 and dx^2+2ex+f=0 have a common root, then

JEE Main Mathematics question

If are in G.P. and the two quadratic equations and have a common root, then

Answer: (A)

GP gives , so the discriminant of is and its (double) root is . Substituting in : , i.e. (using ) , so . Dividing by : , so

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Question ID VK-021965