(1) A qualified county or qualified city may be added to the metropolitan region council after the council’s incorporation upon satisfaction of all of the following requirements:

    (a) A majority of the members elected to and serving on the legislative body of the qualified county or qualified city vote to adopt a resolution stating that the qualified county or qualified city desires to be added to the metropolitan region council and that it accepts the requirements of the articles as amended to reflect the addition of the qualified county or qualified city.

    (b) If a qualified city is proposing to be added to a metropolitan region council that is exercising its authority under section 47(2), that exercise of authority is authorized by a majority of the electors of the city voting on the proposal at the regularly scheduled county primary or general election that follows adoption of the resolution described in subdivision (a). If a qualified county is proposing to be added to a metropolitan region council that is exercising its authority under section 47(2), that exercise of authority is authorized by a majority of the electors of the qualified county voting on the proposal at the regularly scheduled county primary or general election that follows adoption of the resolution described in subdivision (a).

    (c) The articles are amended to reflect the addition of the qualified county or qualified city.

    (2) Upon addition of a qualified county or qualified city to a metropolitan region council, a printed copy of the amended articles shall be filed as required by section 9 by the clerk of the qualified county or qualified city added to the council.