Explicație pas cu pas:
a)
[tex]x = 11k + 1[/tex]
[tex]9989 = 11 \times 908 + 1[/tex]
[tex]\implies 9989 \div 11 = 908 \: rest \: 1[/tex]
b) R: 15 numere
[tex]y = 6 \times c + 1[/tex]
[tex]c = 2 = > y = 6 \times 2 + 1 = 13 \\ c = 3 = > y = 6 \times 3 + 1 = 19 \\ c = 4 = > y = 6 \times 4 + 1 = 25 \\ c = 5 = > y = 6 \times 5 + 1 = 31 \\ c = 6 = > y = 6 \times 6 + 1 = 37 \\ c = 7 = > y = 6 \times 7 + 1 = 43 \\ c = 8 = > y = 6 \times 8 + 1 = 49 \\ c = 9 = > y = 6 \times 9 + 1 = 55[/tex]
[tex]c = 10 = > y = 6 \times 10 + 1 = 61 \\ c = 11 = > y = 6 \times 11 + 1 = 67 \\ c = 12 = > y = 6 \times 12 + 1 = 73 \\ c = 13 = > y = 6 \times 13 + 1 = 79 \\ c = 14 = > y = 6 \times 14 + 1 = 85 \\ c = 15 = > y = 6 \times 15 + 1 = 91 \\ c = 16 = > y = 6 \times 16 + 1 = 97[/tex]
