Final answer:
The function y = -(1)/(x) is undefined when x equals zero due to division by zero being undefined, resulting in an asymptote at x = 0.
Step-by-step explanation:
The function y = -(1)/(x) is undefined when the denominator x is equal to zero because division by zero is not defined in mathematics. This function has an asymptote at x = 0, meaning the function approaches infinity as x approaches zero. This is a common characteristic of functions with a variable in the denominator.