If `z=(3+7i)(a+ib)`, where `a`, `b in Z-{0}`, is purely imaginery, then minimum value of `|z|^(2)` isA. `74`B. `45`C. `65`D. `58`

If `z=(3+7i)(a+ib)`, where `a`, `b in Z-{0}`, is purely imaginery, the

1.	If `z=(3+7i)(a+ib)`, where `a`, `b in Z-{0}`, is purely imaginery, then minimum value of `\|z\|^(2)` isA. `74`B. `45`C. `65`D. `58`
Answer» Correct Answer - D `(d)` `z=(3a-7b)+i(3b+7a)` For purely imaginary, `3a=7b` `impliesa=7` or `b=3` (for least value of `\|z\|`) `implies \|z\|=\|3+7i\|=sqrt(58)`

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If `z=(3+7i)(a+ib)`, where `a`, `b in Z-{0}`, is purely imaginery, then minimum value of `|z|^(2)` isA. `74`B. `45`C. `65`D. `58`

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