the LCM of 42 and 126 using a prime factorization is 2 times 2 times 3
You need at least two numbers to find an LCM.
It is: 126
You need at least two numbers to find a GCF, whichever method you use.
As a product of its prime factors: 2*3*3*7 = 126
2 x 32 x 7 = 126
126 (which is not a prime power factorization) has 12 factors.
2 x 32 x 7
2x3x3x7
It is: 2*32*7 = 126
126 63,2 21,3,2 7,3,3,2
126 63,2 21,3,2 7,3,3,2