Answer:
one because it is cilinder
 
        
                    
             
        
        
        
You can cross multiply
-11(-9) x *( 1)
99=1x
99=x
the answer is 99=x
        
             
        
        
        
The co ordinates of P' is (-7,-2) and Q' is (-16, -8)
<u><em>Explanation</em></u>
PQ is rotated 180 degrees clockwise about P. It means <u>P and P' are the same points</u>. 
According to the graph, the coordinates of P is (-7, -2) and  Q is (2, 4) 
When PQ is rotated 180 degrees clockwise about P, then <u>P or P' will be the mid-point of Q and Q' </u>
Suppose, the co ordinate of Q' is (x, y)
Now according to the mid-point formula, the coordinate of P or P' will be:  , which is actually at (-7, -2)
 , which is actually at (-7, -2)
Thus.....

So, the co ordinates of P' is (-7,-2) and Q' is (-16, -8)