Question

105-30:{54-45:[30-24:(x-15)-7]x15+15:15}=102

Answer 1

105-30:{54-45:[30-24:(x-15)-7]x15+15:15}=102
30:{54-45:[30-24:(x-15)-7]x15+15:15}=105-102 
30:{54-45:[30-24:(x-15)-7]x15+15:15}=3
54-45:[30-24:(x-15)-7]x15+1= 30 : 3
54-45:[30-24:(x-15)-7]x15+1=10
54-45:[30-24:(x-15)-7]x15=10-1
54-45:[30-24:(x-15)-7]x15=9
45:[30-24:(x-15)-7]x15=54-9
45:[30-24:(x-15)-7]x15=45
45:[30-24:(x-15)-7]=45:15
45:[30-24:(x-15)-7]=3
30-24:(x-15)-7=45:3
30-24:(x-15)-7=15
30-24:(x-15)=15+7
30-24:(x-15)=22
24:(x-15)=30-22
24:(x-15)=8
x-15=24:8
x-15=3
x=3+15
x=18