double a=1,b=4,c=4;
double d=SQRT(b*b-4*a*c);
double e=2.0*a;
double x1=(-b+d)/e;
double x2=(-b-d)/e;
printf("X1=%f, X2=%f",x1,x2);
double a=1,b=4,c=4;
double d=SQRT(b*b-4*a*c);
double e=2.0*a;
double x1=(-b+d)/e;
double x2=(-b-d)/e;
printf("X1=%f, X2=%f",x1,x2);