658一元二次方程公式
#include<stdio.h>
#include<math.h>
int main()
{
double a,b,c;
scanf("%lf%lf%lf",&a,&b,&c);
double x=b*b-4*a*c;
if(x<0||a==0)
printf("Impossivel calcular");
else
printf("R1 = %.5lf\nR2 = %.5lf",(-b+sqrt(x))/(2*a),(-b-sqrt(x))/(2*a));
return 0;
}