5x+3=x-4,4y+11=22,11x+68-2x=100-9x,0.1x/0.2-（0.27x+0.18）/0.04=1,（x-1）/2=2-（x+2）/3

5x+3=x-44x=-7x=-7/4----------------4y+11=22,4y=11y=11/4-------------------11x+68-2x=100-9x,9x+68=100-9x18x=100-68x=32/18=16/9-------------------0.1x/0.2-（0.27x+0.18）/0.04=1x/2-(27x-18)/4=12x-27x+18=...