It is: 2, 3 and 7
It i: 2*3*7 = 42
No, prime factorization of 42 is not 21 x 2 because 21 is not a prime number and it can be further broken into primes as 3 x 7. So prime factorization of 42 is 2 x 3 x 7.
19 is already prime; no factorization.
2x2
No.
Prime Factorization: 2*5*31
43 is already prime; no factorization required.
No it isn't. 235/5 = 47 and 47 is a prim number. 235 isn't a prime number so it isn't a prim factorization. The real factorization is 47 * 5.
2 x 3 x 7 = 42 3 x 5 x 7 = 105 3 x 7 = 21, the GCF
115 = 5 × 23
2 x 3
12 = 22 × 3