Sửa giúp em code này với ạ Đề ở dưới Đây là code của em: #include <iostream> using namespace std; int main() { int a, b, c; cin >> a >> b >> c; int tien = ((a+(a*c))*c)/2; double vay = tien - b; if (vay <= 0) cout << 0; else {cout << vay;} return 0; }

A soldier wants to buy w bananas in the shop. He has to pay k dollars for the first banana, 2k dollars for the second one and so on (in other words, he has to pay i-k dollars for the i-th banana). He has n dollars. How many dollars does he have to borrow from his friend soldier to buy ...