Răspuns:
28 a) {-3, -2, -1, 0, 1}
b) {-4, -3, -2, - 1, 0}
c) {-4, 4}
d) {-3, 3}
e) {-8, -7, -6, -5, 5, 6, 7, 8}
30 a) A={-2, -1, 1, 2}
b) B={-8, -7, -6, 6, 7, 8}
c) C)={...... - 10, - 9, -8, -7, 7, 8, 9, 10,.......}
