C :

#include<stdio.h>
#include<math.h>
int main()
{
	int a, b, c;
	double res1, res2;
	scanf("%d%d%d", &a, &b, &c);
	res1 = ((-b) + sqrt(pow(b, 2) - (4 * a*c))) / ((2)*a);
	res2 = ((-b) - sqrt(pow(b, 2) - (4 * a*c))) / ((2)*a);
	if (sqrt(pow(b, 2) - (4 * a*c))==0)
		printf("%.3lf\n", res1);
	else if (sqrt(pow(b, 2) - (4 * a*c)) > 0)
		printf("%.3lf %.3lf\n", res1, res2);
	else
		printf("NOANSWER\n");
	return 0;
}

Pascal :

var a,b,c,d:double;
begin
readln(a,b,c);
if(a=0) then begin writeln('不是二次方程');exit;end;
d:=b*b-4*a*c;
if(d<0) then begin writeln('NOANSWER');exit;end;
d:=sqrt(d);
if(d=0) then begin writeln(-b/(2*a):0:3);exit;end;
writeln((-b+d)/(2*a):0:3,' ',(-b-d)/(2*a):0:3);
end.