To eliminate y, multiply each by whatever is necessary to
cause the coefficients of y in the two equation to be
equal in magnitude by opposite in sign. 

So, multiply both sides of the first equation through by 
Multiply both sides of the second equation through by 



Add term by term:



Divide both sides by 



-------------------



To eliminate x, multiply each by whatever is necessary to
cause the coefficients of x in the two equation to be
equal in magnitude by opposite in sign. 

So, multiply both sides of the first equation through by 
Multiply both sides of the second equation through by 



Add term by term:



Divide both sides by 



Edwin