rt。

#include<bits/stdc++.h>
using namespace std;
constexpr int N = 1e2 + 5;
const double eps = 1e-6;

inline int read(){
	register char ch = getchar();
	register int x = 0;
	register bool f = 0;
	while(!isdigit(ch)) f |= (ch == '-') , ch = getchar();
	while(isdigit(ch)) x = (x << 3) + (x << 1) + (ch ^ 48) , ch = getchar();
	return f ? -x : x;
}

int n;

double a[N][N];

inline int Gauss(){
	bool flag = 0;
	
	int nowline = 1;
	
	for(register int i = 1 ; i <= n ; ++ i) {
		
		for(register int j = i ; j <= n ; ++ j)
			if(fabs(a[j][i]) > eps) {
				swap(a[i] , a[j]);
				break;
			}
		
		if(fabs(a[i][i]) < eps) {
			flag = 1;
			continue;
		}
		
		//for(register int j = 1 ; j <= n + 1 ; ++ j) swap(a[newline][j] , a[nowline][j]);
		for(register int j = n + 1; j >= i ; -- j) a[i][j] /= a[i][i];
		
		for(register int j = i + 1 ; j <= n ; ++ j)
			for(register int k = n + 1 ; k >= i ; -- k)
				a[j][k] -= a[i][k] * a[j][i];
					
		//++ nowline;
	}
	
	if(flag) {
		for(register int i = 1 ; i <= n ; ++ i){
			bool yg = 0;
			for(register int j = 1 ; j <= n ; ++ j) {
				if(a[i][j] != 0) {
					yg = 1;
					break;
				}
			}
			if(yg) continue;
			
			if(fabs(a[i][n + 1]) > eps) return -1;		
		}		
		
		return 0;
	}
	
	for(register int i = n ; i ; -- i)
		for(register int j = i + 1 ; j <= n ; ++ j)
			a[i][n + 1] -= a[j][n + 1] * a[i][j];
	
	return 1;
}

int main(){
	n = read();
	
	for(register int i = 1 ; i <= n ; ++ i)
		for(register int j = 1 ; j <= n + 1 ; ++ j)
			a[i][j] = read();
			
	int backin = Gauss();
	
	if(backin == 1)
		for(register int i = 1 ; i <= n ; ++ i)
			printf("x%d=%.2f\n" , i , a[i][n + 1]);
	
	else printf("%d" , backin); 
	return 0;
}