Final answer:
The expression (5z-3)/(z-1) cannot be evaluated at z = 1 because it results in division by zero, which is undefined.
Step-by-step explanation:
The student has asked to find the value of the expression (5z-3)/(z-1) when z = 1. However, this expression cannot be evaluated at z = 1 because the denominator becomes zero, and division by zero is undefined in mathematics. Therefore, the expression has no value at the given point, and it represents a vertical asymptote or an undefined point in the function's graph.