Answer:
0+7i
Step-by-step explanation:
[tex]\sqrt{-49}=\sqrt{49}\sqrt{-1}=7i=\boxed{0+7i}[/tex]
The real part of the expression ('a') is zero. We have shown that, so it will be in the required form. Ordinarily, 0 would not be shown when writing this number.
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We have taken the question to mean the principal square root. -7i is also a root of -49.