If the petition for annexation filed with the board of commissioners complies with the requirements of law, the board may accept the petition, fix a date for public hearing, and publish notice of the hearing in a newspaper of general circulation in the area proposed to be annexed and also post the notice in three public places within the area proposed for annexation. The notice shall specify the time and place of the hearing and invite interested persons to attend. The expense of publication of the notice shall be paid by the district.