int x = 2;
cout << "2*10=" << 2 * 10 << endl;
Bug 1: you are requested to
print variable x multiplied by 10. What if suddenly x= 5 ?
float y = 1.5;
cout << "1.5/2=" << 1.5 / 2 << endl;
Bug 2: you are requested to
print variable y divided by 2. What if suddenly y= 3.5 ?
char z =5 ;
cout << "z*(z+1)=" << z*(z+1)<< endl;
Bug 3: you are requested to
print the next character after z (aka z+1). You are not requested to print z*(z+1).
Advice: z being a char, z='a' would be more likely.
[Update]
int x ;
float y ;
char z = 'a';
You should give values to x and y
To know if program is ok, just rub it many times and change the values to see if results are ok.