Notice that the x on the right has the understood exponent 1:



1. We multiply the coefficient  by the 
coefficient  and get .  

2. We add the exponent of the x on the left, , and the 
   exponent of x on the right ,

3. We add the exponent of the y on the left, , and the 
   exponent of y on the right ,




4. We complete the addition of the exponents:



5.  We replace the  by 



6.  time  is just 



7. To make a negative exponent positive you move the factor from
   the numerator to the denominator and change the sign
   of the exponent to positive:

8. 

That's it.

Edwin