Explain Hume’s distinction between relations of ideas and matters of fact. How does this distinction relate to the skeptical doubts that he raises about things learned from experience?

Read this article http://www.bartleby.com/37/3/4.html and http://www.bartleby.com/37/3/5.html Explain Hume’s distinction between relations of ideas and matters of fact. How does this distinction relate to the skeptical doubts that he raises about things learned from experience?