I think the limit should be 3, not 5, because the square root of -2 (=3-5) is not real.
Assuming that the limit is 3, the expression is the same as 1/sqrt(3-x), the limit is infinity, an asymptote for the expression.
If the limit for x is 5, the limit of the expression would be -isqrt(2)/2, or -i/sqrt(2), an imaginary number, where i represents the square root of minus 1.