Hi EnolaGayTibbets1, You have a good question and I hope I can help you with that. Generally, both words have a similar meaning and therefore easily confused and misused. 'Firm' typically refers to something that is solid and not easily moved or changed. It's used to talk about physical or structural properties. 'The government took firm action to address the rising crime rates by implementing stricter law enforcement measures.' 'The foundation of the building was firm, ensuring its stability even in the face of strong winds or earthquakes.' 'Strong', on the other hand, refers to something that is able to withstand a lot of pressure or force. 'The CEO made a strong decision to restructure the company and improve its financial performance.' 'He had a strong grip on the handlebars as he rode his bicycle down the steep hill.' So, in your sentence, I would personally opt for firm: President Hoover tried to solve the crisis. But he was not willing to take the firm actions that were needed to end it. (Referring to an action that is not easily changed) I hope this helps. Mark