3x-13/9=14/9
3x=13/9+14/9
3x=3
x=3÷3
x=1
x+(3/4-3/8)=7/8
x=7/8+3/8-3/4
x=5/4-3/4
x=1/25/6+7/9+1/6 5/8-2/5+1/45/6+7/9+1/6 =5/6+1/6+7/9=1+7/9=16/95/8-2/5+1/4=25/40-16/40+10/40=19/40x-(3/4+4/7)采纳吧