2/14 is not equivalent to 3/7
In order for two fractions to be equivalent, you must be able to divide both the numerator and the denominator of both fractions by the same number. For example, 2/4 and 4/8 are equivalent, because you multiply 2 and 4 by 2 to get 4 and 8
2/4 (multiply both by two) = 4/8
Hope this helps!!