[Solved] Find the indefinite integral. \[\int 3 x \left( 5 x ^ { 2 } + 3 \right) ^ { 6 } d x\] Maintenance Plan: A strategy for regularly scheduled maintenance activities intended to ensure the long-term efficiency and reliability of equipment, systems, or buildings. Associated Services: Additional services that are provided with a main product or service to enhance customer satisfaction and experience. Unsought Product: Goods that consumers do not normally think of buying or do not know exist until they see them. Kitchen and Bath Store: A retail outlet specializing in the sale of fixtures, appliances, and accessories for kitchen and bathroom spaces.