What is the sum of $sqrt(-81)$ and $3sqrt(-25)$ ?

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Answer 1 · 2016-03-28T04:03:51

$-21i, -9i, 9i and 21i$ or, in brief, the sum = $(+-6+-15)i$ , where i = $sqrt(-1)$ .

Separately, the complex numbers are i $sqrt81=+-i9$ and i $3sqrt25=3(+-5)i$ .
The sum is $=(+-9+-15)i$ .

What is the sum of sqrt(-81)sqrt(-81) and 3sqrt(-25)3sqrt(-25)?