Final answer:
To make the value of the expression 34-12-:2+7 equal to 18, we need to place parentheses in the expression in the correct positions. However, it is not possible to do so.
Step-by-step explanation:
To make the value of the expression 34-12-:2+7 equal to 18, we need to place parentheses in the expression in the correct positions. Here's how:
34 - (12:2) + 7 = 34 - 6 + 7 = 28 + 7 = 35
This means that it's not possible to place parentheses in the expression to make it equal to 18.