1. at least one
3. intersection
5. True
7. True
9. (3,−1)
11. (1,−1)
13. (5, 4), (−5, 4), (−5,−4)
15. (1, 1)
17. {(−1, 1), (2, 4)}
19. {(3, 3), (−2,−2)}
21. {(3, 0)}
23. {(−2, 1), (−1, 2)}
25. {(1,−1), (3, 1)}
27. {(−3,−1), (1, 3)}
29. {(2, 3), (0, 5)}
31. {(7, 5), (−7,−5)}
33. {(4, 2), (−4, 2), (4,−2), (−4,−2)}
35. {(2, 2), (−2, 2), (2,−2), (−2,−2)}
37. ∅
39. {(1, 2), (−1, 2), (1,−2), (−1,−2)}
41. {(2, 1), (2,−1),(− 113,−26−−√3), (− 113,− 26−−√3) }
43. {(5, 3), (3, 5)}
45. ∅
47. {(0,−2), (3, 4)}
49. {(3, 2), (−4,−32)}
51. {(−2, 1), (2, 1), (−2,−1), (2,−1)}
53. {(2, 5), (−7,−107)}
55. {(2,−2), (2, 2), (165, 246−−√5), (165,− 246−−√5)}