What is the gcf of 42 and 72 using prime factorization?

Answer 1

Bad example. 42 is a factor of 126. Therefore 126 has to be the LCM. By the numbers...

2 x 3 x 7 = 42

2 x 3 x 3 x 7 = 126, the LCM

Answer 2

The prime factors of 42 are 2, 3 and 7. You need at least two numbers to find an LCM.

Answer 3

2 x 3 x 7 = 42

2 x 2 x 2 x 3 x 3 = 72

2 x 3 = 6, the GCF

Answer 4

2 x 2 x 2 x 2 = 16

2 x 3 x 7 = 42

2 x 2 x 2 x 2 x 3 x 7 = 336, the LCM

Answer 5

2 x 7 = 14

2 x 11 = 22

2 x 7 x 11 = 154, the LCM

Answer 6

Since 126 is a multiple of 42, it is automatically the LCM, but if you insist...

2 x 3 x 7 = 42

2 x 3 x 3 x 7 = 126

2 x 3 x 3 x 7 = 126, the LCM

Answer 7

2 x 2 x 2 x 2 = 16

2 x 3 x 7 = 42

2 x 2 x 2 x 2 x 3 x 7 = 336

Answer 8

756