I have assumed that the question mark is meant to be forward slash
2*18-18/2*[28-3*(2+4)]
Always do brackets first (PEDMAS)
The brackets within the brackets take priority:
2*18-18/2*[28-3*6]
Now the multiplication inside the brackets:
2*18-18/2*[28-18]
Now the rest of the bracket
2*18-18/2*10
Now the division:
2*18-6*10
Now the multiplication
36-60
Now the subtraction
-24
Hope this helps :)