3/2x+2y=1 x=(1-2y)*(2/3) x=2/3-4/3y
1/4x+7/4y=2 x=(2-4y)*4 x=8-16y
5x-3y=x+2y (5-1)x=(2+3)y x=5/4y
2（3y-3）=6x+4 6y-6=6x+4 x=(6y-10)/6 x=y-5/3