Question

How do you know that 3/7 is not equivalent to 25/56

Answer 1

3/7 is not equivalent to 25/56 because the two numerators are not equivalent by the same factor as 56 and 7 (which is 8)
Hope this helps

Answer 2

Because if you reduce 25/56 it does not equal 3/7. 5 is not a common factor for both 25 or 56.