X=-5 is your answer. Hope this helps :)
        
                    
             
        
        
        
Answer:
12/13
Step-by-step explanation:
We know that cosine is the adjacent side divided by the hypotenuse in a right triangle. 
The adjacent side to angle C is BC
The hypotenuse is AC because it is opposite to the right angle
So...
cosine is (BC)/(AC)
36/39
12/13
 
        
             
        
        
        
Answer:
 The forecast is accurate within plus or minus 3.2 units
Step-by-step explanation:
Mean Absolute Deviation is a statistical measure of dispersion from forecast. It measures accuracy level of predicted forecast, by averaging the difference between absolute value of each error from forecasted value. 
MAD for a forecast states that : Forecast is accurate within the expected range variation of Mean Absolute Deviation. 
So : If the MAD for a forecast is 3.2, we can say that -  The forecast is accurate within plus or minus 3.2 units