Hey there!!
Okay so let's start simplifying this :D
-| -2 + 9| <---- remember that the "vertical bars" are absolute value signs
Absolute value signs will make any values within them into a positive value even if it was negative in the first place
-| 7 | <---- first simplify what is within the absolute value signs
- 7 <----- this is your final answer!!!
I hope this helps you! ^__^