ANSWER
No, they are not
Step-by-step explanation
Equivalent fractions are fractions that have the same value even though their numerators and denominators are not the same.
This means that if we reduce all the fractions to lowest terms, they must give us the same value.
Let us do that for these fractions:
1/2 - it is in the lowest terms
6/8 = 3/4
1/3 - it is in its lowest terms
3/4 - it is in its lowest terms
We can see that all four fractions are not the same in their lowest terms (except 6/8 and 3/4) and hence, they are not equivalent.