No, they are not. When they are simplified to find if they are equivalent or not, the numerator can be divided out like so:
3xy (3xy) 6xy (6xy)
----------- -------------
4y 8xy
Then the cross-cancel method can be used to simplify the two fractions, which later simplifies to:
3x (3xy) 3 (6xy)
---------- ---------
4 4
Hence, they are not equivalent to each other.
