3x² - 21
Factor 3 from both terms:
3 (x² - 7)
To me, that's as far as you should need to go.  But if you want to get 
completely carried away, you could go one step further, since you have 
the difference of two squares:
3 (x + √7) (x - √7)
Of course, there's no end now, because the last binomial could be
considered another difference of two squares, so you'd have to 
factor that too:
3 (x + √7) (√x + ⁴√7) (√x - ⁴√7)
but to me, this would be nonsense.
        
                    
             
        
        
        
9514 1404 393
Answer:
   21.  D
   22.  C
Step-by-step explanation:
21. The expansion of the given expression is ...
   
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22. The least likely team to make the championship game is the one with the lowest probability.
   3/8 < 1/2 < 2/3 < 4/5
The Bulldogs are least likely to play in the championship game.
 
        
             
        
        
        
The compass heading is 242.5deg
 
        
                    
             
        
        
        
Step-by-step explanation:
f(-5) goes through y=-9
So, f(-5) = -9