3x-2y=5 (1)kx+(k-1)y=7 (2)(2)*5-(1)5kx+(5k-5)y-3x+2y=35-5(5k-3)x+(5k-3)y=30x+y=1所以(5k-3)x+(5k-3)y=5k-3所以5k-3=30k=33/5