Extra Practice exercises are downloadable worksheets of additional practice exercises. Print out these worksheets, work through the exercises, then check your work against the answer page.

Once you've practiced and mastered the basics of systems of equations, refer back to page 493, the first page of Chapter 8, and review the graded gasoline application.

Here's your chance to explore the World Wide Web and practice your new skills at the same time. Explore some related Web sites to learn more about octane levels in gasoline.

After you've practiced and after you've explored, don't forget about your upcoming Chapter Test. Prepare for your exam by working through our Chapter 8 Review, and then check your answers. These free downloadable files are accessible by selecting the Chapter Review button at the top of this page.

Good luck!