#### Answer

Domain: (- infinity, infinity)
Range: {1} U {x|x is irrational number}

#### Work Step by Step

f(x) is defined for all real numbers. This means that the domain of f is set of all real numbers. Value of function is 1 when x is rational and 5x when x is irrational. This means that the range of f consists of 1 and all irrational numbers because when x is irrational, 5x is also irrational.