6 . {3 .[-9 + 4 (5 . 3 - 9)] - 3 . (40 - 8)}
are the dots multiplication??
if so, then it would be:
6⋅3⋅[−9+4(5⋅3−9)]−3⋅(40−8)
(calculate parenthesis) [−9+4(5⋅3−9)]=15
6⋅3⋅15−3(40−8)
(calculate parenthesis) (40−2)=38
6⋅3⋅15−3⋅32
(multiplication) 6⋅3⋅15=270
270−3⋅32
(multiplication) 3⋅32=96
270−96=174
+515 
