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If all the roots of z^3+az^2+bz+c=0 are ...

If all the roots of `z^3+az^2+bz+c=0` are of unit modulus, then (A) `|a|le3` (B) `|b|le3` (C) `|c|=1` (D) none of these

A

`|a|le3`

B

`|b|gt3`

C

`|c|le3`

D

None of these

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