Which of the following methods is NOT a way to vote on a motion?

The method identified as not a way to vote on a motion is unilateral agreement. In parliamentary procedure, voting on a motion typically involves some form of collective decision-making that reflects the preferences of the assembly members.

Voice vote, ballot voting, and roll call voting are all established methods for members to express their approval or disapproval of a motion.

In a voice vote, members vocalize their votes, with the chair determining the outcome based on which side sounds louder. Ballot voting allows members to submit their votes in written form, ensuring confidentiality and often used for more contentious issues. Roll call voting records the votes of individual members, allowing for transparency and accountability.

Unilateral agreement, however, suggests a one-sided decision without the necessary process of voting. This does not align with parliamentary procedure principles, which emphasize the need for participation and expression of the group’s collective will. Thus, unilateral agreement doesn't fit within the context of how formal votes on motions are conducted.