15+2/3x=85
2x/3 = 85-15
2x/3 = 70
x= 105
x-1/5x=1/2
4x/5 = 1/2
x= 5/8
4x+1/3x=8/9
13x/3 = 8/9
x= 24/91
有什么不明白可继续追问
请及时选为满意答案,