For each of the following, determine if the function is increasing, decreasing, even, odd, and/or invertible on its natural domain:
1). \((x) = \sqrt{x-5}\)
2). \(f(x) = \frac{x}{x^2+1}\)
3). \(f(x) = x + 1 + \frac{1}{x}\)
4). \(f(x) = |x| \cdot \sqrt{x}\)
