So we have
(5-6x9+6)x9+3-85
So this is a oder of operation question, firstly you start with the brackets
(5-6x9+6)
B. Brackets
E. Exponents
D. Division
M. Multiplication
A. Addition
S. Subtraction
(5-6x9+6)
Multiplication first
6x9=54
Now we have
(5-56+6)
56+6=62
62-5=57
((57))
Now we have left
57x9+3-85
Start from multiplication
57x9=513
513+3= 516
516-85= 413
413