Dunn and Welch both appeared to operate Ruidoso Downs Feed Concession. Dunn sought to obtain credit for Ruidoso Downs from Anderson Hay and Grain Company. Relying on Dunn's financial position, Anderson extended the credit. Dunn was the person who was responsible for making sure that the payments were made. When Ruidoso Downs could not pay Anderson, Anderson brought an action against Dunn, alleging that, as partner, Dunn was personally liable for the debts the partnership could not repay. Dunn defended on the grounds that he was not a partner because there was no formal partnership agreement between him and Welch. Was Dunn liable? Explain.