1. Remember the PEMDAS rule for order of operations.
First do Parentheses.
(2*9)+(16/4)3* (5-6/2) =
18 + 43 * (5-3) =
18 + 64 * 2 =
18 + 128 = 146
2. First, make sure you see which terms have variables, and which don't. There are some terms with x, some with y, and some with no variable at all.
How many x's are there? 12x and -5x. Add them together to get 7x
How many y's are there? 12y and 3y. That's 15y
What's left over? 17 and 3 = 20
So the sum is 7x + 15y + 20