Make up any 2 numbers for the coefficients of x and y for the first
equation, say  and , so write 

Make up any 2 numbers for the coefficients of x and y in the second
equation, say  and , so write 

So we have the system with left sides only:



Now we just substitute  for  and  for 
in each:



So the first equation will be  



So the second equation will be  

So the final system is:



Edwin