Let f be the function given by f (x) = x + 1/Squareroot 5 - x. What is the domain of f? Let g be the function given by g (x) = 10/Squareroot x - Squareroot 2x - 1. Find and simplify g (1) - 3g (25). Let f be the function given by f (x) = 5x - x^2. Find and simplify f (x + h) - f (x)/h.