5-5/6X=1/3
5/6X=5-1/3
5/6X=14/3
X=14/3÷5/6
X=28/5
X=5.6
X-3/8X-2/8X=15
(1-3/8-2/8)X=15
3/5X=15
X=15÷3/5
X=25
2X+5（30-X）=99
2X+150-5X=99
5X-2X=150-99
3X=51
X=51÷3
X=17