5 DIM A(7,9)
10 PRINT "NO. OF UNKNOWNS?" 
20 INPUT N 
30 PRINT "INPUT 'AUGMENTED COEFFICIENT MATRIX'" 
100 FOR I=1 TO N  
120 INPUT A(I,1),A(I,2),A(I,3),A(I,4),A(I,5),A(I,6),A(I,7),                 A(I,8),A(I,9) 
140 NEXT I  
160 PRINT 
210 FOR S=1 TO N  
220 FOR T=S TO N 
230 IF A(T,S)<>0 THEN 240
235 NEXT T  
237 PRINT "NO UNIQUE SOLUTION"  
238 GOTO 999  
240 GOSUB 510
250 C=1/A(S,S) 
260 GOSUB 610
270 FOR T=1 TO N  
275 IF T=S THEN 300 
280 C=-A(T,S)
290 GOSUB 710
300 NEXT T  
305 NEXT S  
310 GOTO 800
510 FOR J=1 TO N+1  
520 B=A(S,J) 
530 A(S,J)=A(T,J)
540 A(T,J)=B 
550 NEXT J  
560 RETURN 
610 FOR J=1 TO N+1  
620 A(S,J)=C*A(S,J) 
630 NEXT J  
640 RETURN 
710 FOR J=1 TO N+1  
720 A(T,J)=A(T,J)+C*A(S,J) 
730 NEXT J  
740 RETURN 
800 FOR T=1 TO N  
810 PRINT "X(";T;")=";A(T,N+1)  
820 NEXT T  
999 END 

