Answer: -67
Step-by-step explanation: Use PEMDAS, or order of operations. EPIC. Parenthesis, exponents, multiplication, division, addition, subtraction. Lit. Now, the first thing to do is multiply. 18 x 3=54.
54 + 12 - 1 x 34 + 13 - 2 x 56
Multiply 1 x 34 for 34
54 + 12 - 34 + 13 - 2 x 56
Multiply 2 x 56 to get 112
54 + 12 - 34 + 13 - 112
Now addition, so add 54 to 12 for 66
66 - 34 + 13 - 112
You also do the operation from left to right if there is addition and subtraction
66-34 = 32
32 + 13 -112
Add 13 to 32 for 45
45 - 112 = -67