How can I solve a quadratic equations?

Question

In C++

Answer 1

#include <math.h>
int main(){
double a = n
double b = n
double c = n
double result = (b * -1) + sqrt(b * b - 4 * (a * c)) / 2 * a
}

Answer 2

Ramphy Aquino Nova using #include <cmath> is better