#include<stdio.h>
#include<math.h>
int main()
{
	double a, b, c, x, y;
	printf("Moi nhap he so cua phuong trinh: ");
	scanf("%lf %lf %lf", &a, &b, &c);
	double denta = b*b - 4 * a*c;
	if (denta < 0)
	{
		printf("Phuong trinh vo nghiem");
	}
	else if (denta = 0)
	{
		y = -b / 2 * a;
		if (y >= 0){
			printf("k=2");
			printf("Phuong trinh co nghiem kep: x= %lf&& x= -%lf\n", x, x = sqrt(y), x = -sqrt(y));
		}
		else
		{
			printf("Phuong trinh vo  nghiem\n");
		}
	}
	else
	{
		double y1, y2;
		y1 = (-b + sqrt(denta)) / 2 * a;
		y2 = (-b - sqrt(denta)) / 2 * a;
		if (y1 >= 0 && y2 >= 0)
		{
			printf("k=4");
			printf("Phuong trinh co 2 nghiem phan biet: x=%lf && x=%lf\n", x, x = sqrt(y1), x = -sqrt(y1));
		}
		else{
			printf("Phuong trinh vo nghiem");
		}
	}
}