Final answer:
The number of different elements in axb is given by the product of m and n.
Step-by-step explanation:
The number of different elements in the combination axb depends on the values of a and b. If a has m elements and b has n elements, then the number of different elements in the combination is given by the product of m and n.
So, the number of different elements in axb is m * n.
For example, if a has 3 elements and b has 4 elements, then the number of different elements in axb would be 3 * 4 = 12.