Jawabanmu

2014-07-17T09:34:33+07:00
X+2y = 15
x-9y = -8
---------------- (-) eliminasi
   11y =23
       y = 23/11
Subtitusi nilai Y kepersamaan 
X+2y = 15
x + 2 (23/11) = 15
x + 46/11=15
x = 15 -46/11
x = 
2014-07-17T09:50:23+07:00
Dgn cara di eliminasi
X+2Y=15
X-9Y=-8
________  -
11Y=23
Y=23/11