12.3+5x=3.8
5x=3.8-12.3
5x=8.5
x=8.5÷5
x=1.7正确 嘛哦，对不起 12.3+5x=3.8 5x=3.8-12.3 5x=-8.5 x=-8.5÷5 x=-1.7