On number 3 you multiply the number on the outside of the “( )” by the numbers on the inside of the “( )” so 0.5(12m)-0.5(22n) 
Number 4 you do the same... 2/3(18x)+2/3(6z) then you multiply those and then add the answers together.
        
             
        
        
        
Answer:
1,2,4
Step-by-step explanation:
1: The temperature should be decreasing in an exponential rate as the coffee is hot
2: radioactive element should keep decreasing over years
3: should be increasing rate
4: 'popularity is declining' indicates it's a decay
5: 'growing community' indicated it's increasing
 
        
             
        
        
        
Answer: 91
Step-by-step explanation:
95 - 4 (That he gave to Harry) = 91
Hope this helped!