7+(x-3y)/4=2x-(y+5)/3[10(x-y)-4(1-x)]/3=y去分母7*12+3(x-3y)=12*2x-4(y+5)10(x-y)-4(1-x)=3y整理得：21x+5y=10414x-13y=4①*2②*3得42x+10y=20842x-39y=12解得 y=4 x=4③④⑤