3x-y=2k-1 (1)
4x+2y=k (2)
(1)*2+(2)
10x=4k-2+k=5k-2
x=(5k-2)/10
由(1),y=3x-2k+1=3(5k-2)/10-2k+1
x>0,(5k-2)/10>0,5k-2>0,k>2/5
y>0,3(5k-2)/10-2k+1>0.3(5k-2)/10>2k-1,15k-6>20k-10,5k
3x-y=2k-1 (1)
4x+2y=k (2)
(1)*2+(2)
10x=4k-2+k=5k-2
x=(5k-2)/10
由(1),y=3x-2k+1=3(5k-2)/10-2k+1
x>0,(5k-2)/10>0,5k-2>0,k>2/5
y>0,3(5k-2)/10-2k+1>0.3(5k-2)/10>2k-1,15k-6>20k-10,5k