Describe the piecewise function below by evaluating the function for given values of the domain

We have a piecewise function.
 Therefore, to find the function, we must evaluate each domain separately.
 We have then:

 For :
 The function for this domain is:
 

 For :
 The function for this domain is:
 
 Where,
 
 
 Substituting:
 

 For :
 The function for this domain is:
 

D.