(1)y=x,y+4x=15; (2)x+2x-3y=1; (3)x-7y=0,x-9y=8=0.

问题描述:

(1)y=x,y+4x=15; (2)x+2x-3y=1; (3)x-7y=0,x-9y=8=0.

x=3,y=12
x=y+1/3