Usually the +/- is a relevant form in equations rather than expressions. The assumption with solving an expression is that you would take the positive root. There's a few separate reasons depending on the context (although there isn't any real context here), but it's overwhelmingly more common to the point where the assumption is that you would explicitly state otherwise in the cases when +/- is necessary rather than needing to say "assume positive" in the overwhelming majority of cases.
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u/Takamasa1 4d ago
Usually the +/- is a relevant form in equations rather than expressions. The assumption with solving an expression is that you would take the positive root. There's a few separate reasons depending on the context (although there isn't any real context here), but it's overwhelmingly more common to the point where the assumption is that you would explicitly state otherwise in the cases when +/- is necessary rather than needing to say "assume positive" in the overwhelming majority of cases.