Step 1 :

The functions are and .

(a)

The solution is .

Step 2 :

(b)

The solution is .

Step 3 :

(e)

The solution is .

Step 4 :

(f)

Rewrite the inequality.

This product can be greater than zero (positive) if both factors are positive or both factors are negative.

Step 5 :

Case 1: 

Both factors are positive.

The only condition that makes both true at .

Case 2: 

Both factors are negative.

The only condition that makes both true at .

The solution is .

Solution :

(a) The solution is .

(b) The solution is .

(e) The solution is .

(f) The solution is .