-2x-11y=3c (1)
6x+29y=-7c (2)
(1)*3+(2)得:
-4y=2c
解得:
y=-c/2
把y=-c/2代入(1)得:
-2x+11c/2=3c
2x=11c/2-3c
2x=5c/2
解得:x=5c/4