For which values of the Boolean variables x, y and z does x + y + z = xyz? Solution A conjunction xyz is 1 (true) only when x = y = z = 1 and 0 otherwise. The disjunction is 0 when x = y = z = 0 and 1 otherwise. These two only share values then when either x = y = z = 0 or x = y = z = 1. That is, when x, y, z are equal, all true or all false..