A couple of rules to review:
#1). Ln(the square root of a number) = 1/2 Ln(the number)
and
#2). e^(Ln of a number) = the number
Now we're all set to solve this thing.
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Ln( square root of(x+2) ) = 3
From Rule #1: 1/2 Ln (x+2) = 3
Multiply each side by 2: Ln (x+2) = 6
From Rule #2: (x + 2) = e^6
(x + 2) = 403.43 (rounded)
Subtract 2 from each side: x = 401.43 (rounded)