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ISI2017-PCB-A-1

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Let the roots of the cubic equation be α,β and ϒ . 

We know, in a cubic equation of the form ax3 + bx2 + cx + d = 0 .

Sum of roots α+β+ϒ = -b/a = 0 . From this we can conclude that atleast one root is negative. 

Product of roots αβϒ= -d/a = -(-2017)/1 = 2017 . 

From this there is only one combination possible which is 2 roots are negative and one is positive. 

Hence it can be concluded that exactly one root is positive 

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