Question 992474
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1)

{{{system(2x+3y=18,
4x+6y=12)}}}.


Divide the second equation by 2. You will get 


{{{system(2x+3y=18,
2x+3y=6)}}}.


Now compare two equations in this system. They have the same left parts and different right parts.


Hence, the system is inconsistent. You need not to make long calculations. You can establish it in couple lines.



2) The same approach works for the second system, too.