The answer is 3
Answer Explanation:
        
             
        
        
        
That equation can represent the relationship among the image distance, 
object distance, and focal length of a lens.  
It could describe the effective resistance of two resistors in parallel, the 
effective inductance of two coils in parallel, or the effective capacitance 
of two capacitors in series.  
Thanks for sharing it.  Now, did you have a question to ask ? 
        
             
        
        
        
Answer:
A subject and a predicate
Step-by-step explanation:
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