4.（1)3*x (2)3*x+y (3) (x+y)/7 (4)(3*x+y)/(z+2) 

5. bcbc

6. 0

7.

#include 
     
      using namespace std;int main( ){　　int num1,num2;　　cout<<"Enter the divendend:";　　cin>>num1　　cout<<"Enter the divisor:";　　cin>>num2;　　quotient=num1/num2;　　remainder=num1%num2;　　cout<
      
       <<"divided by"<
       
        <<"is"<
        
         <<"\n";　　cout<<"with a remiander of"<
         
          <<"\n"; 　　return 0;}
         
        
       
      
     

 

8.a.52.0

b. the program only transfer 20 celsius degree into fahrenheit, the programmer wanted to input the degree that needs to be transferred. Also the 9/5 gives back a whole number instead the exact result of 9/5, so need to be rectified as 5.0/9.

c

double c;cout<<"input the degree Celsius.";cin<