去括号,合并:4x+x/2=99 9x/2=99 x=22
x-2+x+2+x/2+2x=999x/2=99x=22
(x-2)+(x+2)+(x/2)+2x=99x-2+x+2+x/2+2x=994x+x/2=999x/2=999x=198x=22