can you help me answer those questions?

Question

1) when solving equations with absoulte value, why do we need to consider two equations?
2) A compound inequality uses one of the words and or. How can we determine whether to use intersections or union when graphing the solution set?

Answer 1

1) when solving equations with absoulte value, why do we need to consider two equations?
because there are 2 cases: either x>=0 or x<0. .

Answer 2

1)
because
|-a| ≡ a
AND
|a| ≡ a

2) A compound inequality is the intersection of the two inequalities taken separately.