3x-5/6x=13/18
两边同时乘以18
54x-15x=13
39x=13
x=1/3
5x-5/6=5/12
5x=10/12+5/12
5x=15/12
x=1/4
75-2/5
=75-0.4
=74.6
75+2/5
=75+0.4
=75.4额.................是分数加减法75-2/5 =375/5-2/5 =373/575+2/5 =375/5+2/5 =377/5我刚刚做的就是对的呢保证正确...3x-5/6x=13/18不懂3x-5/6x=13/18 54x/18-15x/18=13/18 39x/18=13/18 x=13/18÷39/18 x=1/3我之前做的是去分母呢