Final answer:
The question asks to evaluate the expression z(x - 1), but the various values provided for z and x do not align to allow us to solve it without further context or instructions.
Step-by-step explanation:
The student's question relates to evaluating the expression z(x - 1) with given values for z and x. However, the values for z and x are provided in separate equations, and we need to find a pair of values where both variables are defined under the same equations. The provided equations do not give a straightforward solution because they contain different values for x and z. An evaluation is not possible without additional context or a specific pair of values to use. In the field of mathematics, when faced with multiple potential values, one needs a clear definition of which specific values to use for the variables in the expression.