The answer is 18 beacause 6+6+2+4=18
Are you missing something?
2xy=7
5xy=9
does not have a solution.
If you mean
2x+y=7
5x+y=9
please say so.
The third story, to get area you have to multiply length times width
This would be.
-23√6 all over 6.
Or: around -9.39