Answer :

GCF(14; M) = 210

210|2
105|5
  21|3
    7|7
    1|

210 = 14 × 3 × 5

The possible values of M:
14 × 1 = 14
14 × 2 = 28
14 × 4 = 56
14 × 7 = 98
14 × 8 = 112
14 × 11 = 154
14 × 13 = 182
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