-|-10|-(-10)
A negative outside of the “ | “ means that one number inside will be negative . -10-(-10)
An imaginary | will “appear” in between the two negative signs or it will turn into an addition sign.
-10+10
A positive subtracts negatives from the negative number. The answer is 0
I hope this helped.
Step-by-step explanation:
(b) If 
then
Note that 
cancel out so we get
Solving for 
we get
(c) I'm not sure what the problem is asking for but here goes. As r doubles, 
becomes
