Huh? not sure what you mean
        
                    
             
        
        
        
Given that I no not see any explanation in the previos answer, I think you can benefit of this.
Exothermic refers only to the fact that the reaction releases energy in the form of heat when occurs. So, the enthalpy is higher at start and lower and the end.
Seen in this way, you can deduct that the change in enthalpy is negative, which is what the third option says.  
        
                    
             
        
        
        
1,36. 2,18. 3,12. 4,9. 6,6. I thibk thats all
        
             
        
        
        
Answer:
x=9 and z=83
Step-by-step explanation:
First you subtract 97 from 180 because that gives you z because 180 is a flat angle and 83 plus 97 gives 180. For x the opposite angle is also 97 so you set the equation 5x + 52 = 180 and you solve for x to get the x value. Hope this helps :)