Answer:
3
Step-by-step explanation:
(f O g) this basically means that the input x first goes trough the function g and then f. Like f(g(x)).
So when x went trough g, you got the output g(x) and then this went trough f and you got f(g(x)) = -8 = 'f(x)'.
With this in mind you can retrace your steps by first looking at what input can get -8 as an output, for f this is -4. this means g(x) = -4
Then you look at what input (this is the x you're looking for) gets you the ouput -4. Looking at the second image you'll picture see that it's the input 3. 
 
        
             
        
        
        
Answer:
15
Step-by-step explanation:
30 / 2 = 15
 
        
                    
             
        
        
        
2 is less than is greater than or equal to 4 and less than or equal to 9.
        
             
        
        
        
Answer:
no solution.
Step-by-step explanation: