Question 102485
The first problem is not clear. Did you mean to use brackets or the absolute value sign?

Number 2:

|-5 + 12 | + ( -7)
First add the numbers within the absolute value signs.
|7| + (-7)
Then take the absolute value, which is a given number's distance from zero. In other words you keep the same number as what is inside the absolute value signs, but always make it positive
7 + (-7)
This is the same as
7 - 7
 =0

Number 3:

-|-11+6|
First add the numbers within the absolute value signs.
-(|-5|)
Then take the absolute value.
-(5)
We are left with -5.
The two negatives don't cancel out because one disappears when you take the absolute value. You are left with one negative, which is present in your answer.