1. 1,2,3,6 2. 1,3,9 3. 1,2,5,10 4. 1,2,3,4,6,12 5. 1,3,7,21 6. 1,2,3,6,9,18 7. 8,16 8. 1,5,25 9. 1,31 10. 3x3 11. 5x5 12. 2x2x2 13. 14 is a composite number 14. 2x2x2 15. 3x5 16. 5 is a prime number 17. 20 is a composite number 18. 2x13
When you graph these two equations on a graphing calc, you should be able to see one dotted line and one solid, as well as the solutions being mostly in the 1st quadrant.