Question 7255
(3xyz^2 )(2y)
____________  
(6y^4)(xz^4)
..x above and below shall be cancelled

   (3yz^2 )(2y)
=> ____________  
   (6y^4)(z^4)
...by multiplying the numerator and the denominator
=> 6y^2z^2
   _______
   6y^4z^4
...y's powers above i.e. 2 shall be subtracted from 4 u get 2 in the denominator 'y' and above 'y' is cancelled 
=> 6z^2
   _______
   6y^2z^4
..same as wid 'z' denominator's z shall have power 2 now and 6 shall de reduced
=>1/(y^2z^2)