Answer:
39
Explanation:
1) Remove parentheses.
18 + 21
2) Simplify.
39
Thanks,
Eddie
Quick hint:
When there is a number and then a - sign outside the parenthesis and on the inside, then it creates a figure similar to the plus sign, that is when you just make it one.
Add the two numbers (both are always positive in this instance),
and there's your answer!