Michigan Compiled Laws, Chapter 450. Corporations § 450.2415

Sec. 415. (1) Unless a greater or lesser quorum is provided in the articles of incorporation, in a bylaw adopted by the shareholders, members, or incorporators, or in this act, shares or members entitled to cast a majority of the votes at a meeting constitute a quorum at the meeting.If the withdrawal of shareholders or members leaves less than a quorum before adjournment, the remaining shareholders or members present in person or by proxy at the meeting may continue to do business until adjournment. Whether or not a quorum is present, a meeting may be adjourned by a vote of the shareholders or members present.

(2) If the holders of a class of shares or members of a class are entitled to vote separately on an item of business, this section applies in determining the presence of a quorum of the class for transaction of the item of business.