The order of operations is:
Parentheses/Groupings, 
Exponents, 
Multiplication/Division, from left to right, 
Addition/Subtraction, from left to right
35. (31-9) - 12 ÷ 2 
22-12 ÷ 2 
22-6
=16
 36. 36 ÷ 3 +72 ÷ 9 
12 + 72 ÷ 9 
12+8
=20
37. 8(16-7)
8(9)
=72
38. 100-28 x 2 
100-56
=44
I hope this helps!