You can dispose a number [tex] x [/tex] of elements in a matrix-like formation with [tex] n\times m [/tex] shape if and only if [tex] n [/tex] and [tex] m [/tex] both divide [tex] x [/tex], and also [tex] nm=x [/tex].
So, we need to find the greatest common divisor between [tex] 104 [/tex] and [tex] 96 [/tex], so that we can use that divisor as the number of columns, and then.
To do so, we need to find the prime factorization of the two numbers:
[tex] 104 = 2^3\times 13 [/tex]
[tex] 96 = 2^5 \times 3 [/tex]
So, the two numbers share only one prime in their factorization, namely [tex] 2 [/tex], but we can't take "too many" of them: [tex] 104 [/tex] has "three two's" inside, while [tex] 96 [/tex] has "five two's" inside. So, we can take at most "three two's" to make sure that it is a common divisor. As for the other primes, we can't include [tex] 3 [/tex] nor [tex] 13 [/tex], because it's not a shared prime.
So, the greater number of columns is [tex] 2^3=8 [/tex], which yield the following formations:
[tex] 104 \to 8\times 13 [/tex]
[tex] 96 \to 8\times 12[/tex]
