#include
#include
int main(void)
{
float a,b,c,x,y,z;
printf("please input a, b and c:");
scanf("%f %f %f", &a, &b, &c);
z = b * b - 4 * a * c;
if (a == 0) {
printf("a = 0\n");
return 0;
}
if (z < 0) {
printf("b*b - 4ac < 0\n");
return 0;
}
a *= 2;
if (z == 0) {
printf("x1 = x2 = %f\n", -b / a);
z = sqrt(z);
x = (z - b) / a;
y = (-z- b) / a;
printf("x1 = %f, x2 = %f\n", x, y);
return 0;
}