Go: package main

import (
        "fmt"
        "bufio"
        "os"
)

func main() {
        var a, b, c, d, e, f float64
        sc := bufio.NewScanner(os.Stdin)
        for sc.Scan() {
                fmt.Sscanf(sc.Text(), "%f %f %f %f %f %f", &a, &b, &c, &d, &e, &f)

                det := a*e - b*d
                x := (e*c - b*f) / det
                y := (a*f - c*d) / det
                fmt.Printf("%04f %04f\n", x, y)
        }
}

C++: #include <iostream>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <numeric>
#include <string>
#include <vector>
#include <list>

#include <cstdio>

#define DIM 2

typedef std::vector<double> Vec;
typedef std::vector<Vec> Mat;
typedef std::pair<Mat,Vec> Eq;

int main(void){
	using namespace std;

	list<Eq> input;

	double a,b,c,d,e,f;

	cout << fixed << setprecision(3);

	while(cin >> a >> b >> c >> d >> e >> f){
		Vec m1, m2;
		m1.push_back(a);
		m1.push_back(b);
		m2.push_back(d);
		m2.push_back(e);

		Vec vec;
		vec.push_back(c);
		vec.push_back(f);

		Mat mat;
		mat.push_back(m1);
		mat.push_back(m2);

		Eq eq = make_pair(mat,vec);

		input.push_back(eq);
	}

	for(auto itr = input.begin(); itr!=input.end(); ++itr){
		auto mat = itr->first;
		auto vec = itr->second;

		Vec output(DIM);

		auto det = mat[0][0] * mat[1][1] - mat[0][1] * mat[1][0];
		std::transform(vec.begin(), vec.end(),vec.begin(), std::bind1st(multiplies<double>(),1.0/det));

		mat[0][1] = -mat[0][1];
		mat[1][0] = -mat[1][0];
		swap(mat[0][0],mat[1][1]);

		for (int i=0; i<DIM; i++){
			output[i] = inner_product(vec.begin(), vec.end(), mat[i].begin(), 0);
		}

		// cout << output[0] << " " << output[1];
		printf("%.3f %.3f\n",output[0],output[1]);
	}

}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){

  double a,b,c,d,e,f;

  cin >> a >> b >> c >> d >> e >> f;
  
  if(c*e==f*b||a*e==d*b) printf("0.000 ");
  else printf("%.3f ",(c*e-f*b)/(a*e-d*b));
  if(c*d==f*a||b*d==e*a) printf("0.000\n");
  else printf("%.3f\n",(c*d-f*a)/(b*d-e*a));

  return (0);
}

C++: #include<iostream>

double a, b, c, d, e, f;
bool flag;

int main()
{
	while(std::cin>>a>>b>>c>>d>>e>>f)
	{
		double x = (e*c-b*f)/(a*e-b*d);
		double y = (-d*c+a*f)/(a*e-b*d);
		printf("%8.3f %8.3f\n",x,y);
	}
	return 0;
}

C++: //Simultaneous Equation

#include <iostream>
#include <cstdio>
#include <cassert>
#include <cmath>
#include <cfloat>

namespace {

inline bool is_nearly_zero(double x)
{
  if (abs(x) < DBL_EPSILON)
    return true;
  else
    return false;
}

}

int main()
{
  while (1) {
    double x, y;
    double a, b, c, d, e, f;
    std::cin >> a >> b >> c >> d >> e >> f;
    if (std::cin.fail()) break;

    const double det = (a * e) - (b * d);
    assert(!is_nearly_zero(det));

    const double inv_mat[2][2] = {
    	{e, -b},
    	{-d, a}
    };

    x = ((inv_mat[0][0] * c) + (inv_mat[0][1] * f)) / det;
    y = ((inv_mat[1][0] * c) + (inv_mat[1][1] * f)) / det;

	if (is_nearly_zero(x)) x = 0.0;
	if (is_nearly_zero(y)) y = 0.0;
	
    printf("%.3f %.3f\n", x, y);
  }

  return 0;
}

C++: #include<iostream>
#include<iomanip>

using namespace std;

int main()
{
	double a, b, c, d, e, f;
	double x, y;
	double odd;

	while (cin >> a >> b >> c >> d >> e >> f)
	{
		odd = b / e;

		x = (c - odd*f) / (a - odd*d);
		y = (c - a*x) / b;

		cout << fixed << setprecision(3);
		cout << x << " " << y << endl;

	}


	return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<vector>
using namespace std;

int main() {
	double a, b, c, d, e, f, xx, yy;
	while (cin >> a >> b >> c >> d >> e >> f) {
		double y = (a * f - c * d) / (a * e - b * d);
	   　　 double y = (c*d - a * f) / (b*d - a * e);
		cout << fixed << setprecision(3) << x << " " << y << endl;
	}

	return 0;
}

C++: #include <iostream>
#include <cstdio>
using namespace std;
 
int main() {
    double a, b, c, d, e, f;
    while (cin >> a >> b >> c >> d >> e >> f) {
        double y = (c*d - a * f) / (b*d - a * e);
        double x = c / a - b * y / a;
        x *= 1000;
        x = (int)(x + 0.5 - (x < 0));
        x /= 1000;
        y *= 1000;
        y = (int)(y + 0.5 - (y < 0));
        y /= 1000;
        printf("%.3f %.3f\n", x, y);
    }
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int main(){
  double m[2][2],ans[2],rev[2][2];
  while(cin >>m[0][0]>>m[0][1]>>ans[0]>>m[1][0]>>m[1][1]>>ans[1]){
    double det = m[0][0]*m[1][1]-m[0][1]*m[1][0];
    rev[0][0] = m[1][1]/det;
    rev[0][1] = -m[0][1]/det;
    rev[1][0] = -m[1][0]/det;
    rev[1][1] = m[0][0]/det;
    double x = ans[0]*rev[0][0]+ans[1]*rev[0][1];
    double y = ans[0]*rev[1][0]+ans[1]*rev[1][1];
    printf("%.3lf %.3lf\n",x,y);
  }
  return 0;
}

C++: #include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <iomanip>

#define REP(i,n) for(i=0; i < (n); i++)
#define REPONE(i, n) for(i=1; i <= (n); i++)
#define LOOP(n) for(int loopCount=1; loopCount <= (n); loopCount++)
#define ITER(c) __typeof((c).begin())
#define EACH(c,it) for(ITER(c) it =(c).begin(); it!=(c).end(); it++)
#define SZ(c) ((int) (c).size())
#define ALL(c) c.begin(), c.end()
#define SUM(c) accumulate(ALL(c), 0)
#define EXIST(c,v) (find(ALL(c), (v)) != (c).end())
#define PB push_back
#define MP make_pair

using namespace std;
static const double EPS = 1e-9;
static const double PI = 3.141592653589793238462643383279;
typedef long long ll;

int main(){
    int a, b, c, d, e, f;
    while(cin>>a>>b>>c>>d>>e>>f){
        double det = a*e-b*d;
        double x = (c*e-b*f)/det;
        double y = (a*f-c*d)/det;
        x = (int)(x*1000)/1000.0;
        y = (int)(y*1000)/1000.0;
        printf("%.3f %.3f\n", x, y);
    }
    return 0;
}

C++: #include <stdio.h>

int main(){
    int a,b,c,d,e,f;
    double x,y;
    
    while (scanf("%d %d %d %d %d %d",&a,&b,&c,&d,&e,&f) != EOF) {
        x=(double)((c*e-b*f)/(a*e-b*d));
        y=(double)((c*d-a*f)/(b*d-a*e));
        if(-0.0005<x && x<=0)
            x=0;
        if(-0.0005<y && y<=0)
            y=0;
        printf("%.3f %.3f\n",x,y);
    }
    
    return 0;
}

C++: #include<iostream>
#include<algorithm>

using namespace std;

double a, b, c, d, e, f;
double x, y;

int main(){
	while (1){
		cin >> a >> b >> c >> d >> e >> f;
		y = (c - f*a / d) / (b - e*a / d);
		x = -b / a*y + c / a;
		cout << x << " " << y << endl;
	}
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <cmath>
using namespace std;
const double eps = 1e-5;

bool equals(double a, double b) {
  return abs(a-b) < eps;
}

int main() {
  int a, b, c, d, e, f;
  while(cin >> a >> b >> c >> d >> e >> f) {
    double y = (d*c-a*f)/(double)(d*b-a*e);
    double x = (f-e*y)/(double)d;
    if(equals(x,0.0)) x = 0;
    if(equals(y,0.0)) y = 0;
    printf("%.3f %.3f\n", x, y);
  }
  return 0;
}

C++: #include <cstdio>

int main(){
	int a,b,c,d,e,f;
	double g;

	while(scanf("%d %d %d %d %d %d",&a,&b,&c,&d,&e,&f)!=EOF){
		g=a*e-b*d;
		printf("%lf %lf\n",(e*c+(-b)*f)/g,((-g)*c+a*f)/g);
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
long long gcd(long long a,long long b)
{
    while(b!=0)
    {
        a=a%b;
        swap(a,b);
    }
    return a;
}
int main()
{
    int a,b,c,d,e,f;
    while(cin>>a>>b>>c>>d>>e>>f)
    {
        double x,y;
        x=((c*d)-(f*a))/((b*d)-(e*a));
        y=((c*e)-(f*b))/((a*e)-(d*b));
        printf("%.3lf %.3lf\n",y,x);
    }
}

C++: #include<stdio.h>
int main()
{
	double a,b, c, d, e, f, x,y;
	while(scanf("%lf%lf%lf%lf%lf%lf",&a,&b,&c,&d,&e,&f)!=EOF)
	{
		x=(e*c-b*f)/(e*a-b*d);
		y=(c-a*x)/b;
		printf("%.3f %.3f\n",x,y);
	}
}