No municipality or county shall exercise any of the powers conferred upon municipalities and counties by this chapter until after its local governing body has adopted a resolution finding that:

(1) One or more slum areas exist in such municipality or county; and

(2) The rehabilitation, conservation, or redevelopment, or a combination thereof, of such area or areas is necessary in the interest of the public health, safety, morals, or welfare of the residents of the municipality or county.