Question 72494
 1. ((4x^2)/(5y)) * ((7y)/(12x^4)) 

     sol :: 7 /( 15 x^2)

 2. ((8y-4)/(10y-5)) * ((5y-15)/(3y-9))  

     sol ::  4/3


 3. ((x^(2)-4)/(x^(2)-1)) * ((x+1)/(x^(2)+2x)) 
          
     sol :: (x-2)/(x)(x-1)