Answer:
A. Subtract x from both sides: (i.e. 5+x-12 = x-7 <--> 5-12 = -7)
This equation is identically true, so it holds no matter what x is.
B. This one is pretty self-explanatory
Step-by-step explanation:
u wrote the question wrongly the answer is in answer box
This question also my teacher gives me 
hope it helps
 
        
             
        
        
        
Answer:N<-12
Step-by-step explanation:
 5+2n<-19 
Subtract 5 from both sides 
2n< -24
Then divide both sides by two 
N<-12