<h2>(-∞,∞) </h2>
Step-by-step explanation:
PART A:
given 

This is true for all values of x.
So,x∈
-∞,+∞
PART B:
When
,left hand side=
right hand side=
so,left hand side =right hand side
When
,left hand side=
right hand side=
so,left hand side =right hand side
When
,left hand side=
right hand side=
so,left hand side =right hand side