Someone

terminado[duro@FireMachine ~]$ cat mat.c
#include <stdio.h>
#include <stdlib.h>

main(){
        int a,b,c;
        float k;
        float mat[4][5]={
                {2,3,1,3},
                {1,2,1,1},
                {-1,4,0,-2}};

/*
 for(a=1;a<=3;a++){
        for(b=1;b<=4;b++){
                mat[a][b]=a*b;
                printf("   %.2f  ",mat[a][b]);
                        }
        printf(" \n");
}
*/


printf("venga... vamos a empezar... \n");
a=1;
for(a=1;a<=2;a++){
        //k=(mat[1][a]/mat[b][a])*-1;
        for(b=a+1;b<=3;b++){
        k=(mat[1][a]/mat[b][a])*-1;
        printf(" %.2f  \n",k);
                for(c=1;c<=4;c++){
                        mat[b][c]=k*mat[b][c]+mat[1][a];
                        printf("%.2f \n",mat[b][c]);
                }
        }
a=3;
}


for(a=1;a<=3;a++){
        for(b=1;b<=4;b++){
                /*gotoxy(b*5,a)*/printf("   %.2f  ",mat[a][b]);
        }
        printf(" \n");
}

printf("terminado");
return(0);
}

[duro@FireMachine ~]$ cat matriz.c 
#include <stdio.h>
#include <stdlib.h>

main(){
        int a,b,c;
        float k;
        float mat[4][5];

for(a=1;a<=3;a++){
        for(b=1;b<=4;b++){
                mat[a][b]=a*b;
                /*gotoxy(b*5,a)*/printf("   %.2f  ",mat[a][b]);
                        }
        printf(" \n");
}


printf("venga... vamos a empezar... \n");

for(a=1;a<=2;a++){
        //k=(mat[1][a]/mat[b][a])*-1;
        for(b=2;b<=a+1;b++){
        k=(mat[1][a]/mat[b][a])*-1;
        printf(" %.2f  \n",k);
                for(c=1;c<=4;c++){
                        mat[b][c]=k*mat[b][c]+mat[1][a];
                        //printf("%.2f \n",k*mat[b][c]);
                }
        }
}


for(a=1;a<=3;a++){
        for(b=1;b<=4;b++){
                /*gotoxy(b*5,a)*/printf("   %.2f  ",mat[a][b]);
        }
        printf(" \n");
}

printf("terminado");
return(0);
}
[duro@FireMachine ~]$