1/9﹛1/7[1/5﹙X+2/3﹚+6]+8﹜=1
1/7[1/5﹙X+2/3﹚+6]+8=9
1/7[1/5﹙X+2/3﹚+6]=1
1/5﹙X+2/3﹚+6=7
1/5﹙X+2/3﹚=1
X+2/3=5
x=5-2/3
x=4又1/3