{x-2y=6,kx-(k-1)y=5的解x与y互为相反数,求k的值

x与y互为相反数
即x+y=0
y=-x
x-2y=6,
x-2(-x)=6
x+2x=6
3x=6
x=2
y=-2
kx-(k-1)y=5
k*2-(k-1)*(-2)=5
2k+2(k-1)=5
2k+2k-2=5
4k=7
k=7/4