Important: 
When all variables occur only as denominators, then
DO NOT CLEAR OF FRACTIONS!!!.  Instead leave the fractions and
use elimination:

To eliminate y, multiply the second equation through by 3



Add corresponding terms:





Take reciprocals of both sides:



Multiply both sides by 11









Now substitute  for  in one of the original
equations:





NOW it is OK to clear of fractions,
Multiply through by 10y:











Edwin