Mich. Comp. Laws § 141.1006

Sec. 6. The bonds or obligations may be serial bonds or term bonds or a combination of serial and term bonds, shall mature in not more than 30 years, may bear interest at a rate or rates, may be subject to redemption prior to maturity with or without premium, may be sold in 1 or more series at public or private sale at a discount of not to exceed 10% of the principal amount of the bonds or obligations, and may have other terms and conditions all as determined by resolution of the legislative body of the city or county.