Va rog am mare nevoie urgent ex 14 de la a la d(a, b, c, d)!

a) n apartine {1, 2, 3, 6}
b) n apartine {-1, 0, 1, 4, 7, 16}
c) n apartine {0, 2}
d) n apartine {-2, -1, 0, 1}