x-3/4x+6=12
解:1/4x+6=12
1/4x+6-6=12-6
1/4x=6
1/4x÷1/4=6÷1/4
x=24
x=24
x-3/4x+6=12(1-3/4)x=12-61/4x=6x=24
x(1-3/4)=12-61/4x=6x=24