Respuesta :

126:2 = 63 → 1st PRIME FACTOR = 2
63:3 = 21  → 2nd PRIME FACTOR = 3
21:3 = 7    → 3rd PRIME FACTOR = 3
7: 7 = 1    → 4th PRIME FACTOR = 7

Then 126 = 2 x 3² x 7