tolong...!!! jawab plisss butuh banget semoga yang jawab masuk surga

6x - 6y = 18 (dibagi 2)
3x - 3y = 9
ax + 3y = 5
----------------- +
3x + ax = 14. x = 4
3.4 + a.4 = 14
12 + 4a = 14
4a = 14-12
4a = 2
a = 2/4
a = 1/2