这才叫粗暴AC（初学者专用）

#include<bits/stdc++.h>
using namespace std;

int main(){
	double a,b,c,x1,x2;
	cin>>a>>b>>c;
	x1=(-b+sqrt(b*b-4*a*c))*10000/(2*a);
	x2=(-b-sqrt(b*b-4*a*c))*10000/(2*a);
	if(a==0||b*b-4*a*c<=0){
		cout<<"No answer!";
		return 0;
	}
	if(x1<x2){
		cout<<"x1=";
		cout<<fixed<<setprecision(5)<<x1/10000;
		cout<<";x2=";
		cout<<fixed<<setprecision(5)<<x2/10000;
		return 0;
	}
	if(x1>x2){
		cout<<"x1=";
		cout<<fixed<<setprecision(5)<<x2/10000;
		cout<<";x2=";
		cout<<fixed<<setprecision(5)<<x1/10000;
		return 0;
	}
	if(x1==x2){
		cout<<"x1=x2=";
		cout<<fixed<<setprecision(5)<<x2/10000;
		return 0;
	}
}