Question

Does anyone know how to this cause I need to know how to do it.

Answer 1

(a)= 10

(b)=4

Explanation:

the lines are absolute value, so anything in the lines will be positive

Answer 2

Those lines mean absolute value which always positive.
|-3| + 7 could be re-written as 3 + 7
|-3 + 7| could be re-written as 3 + 7