Question 869304
1	x	+	1	y	+	1	z	=	0			--------------				1
1	x	+	-1	y		4	z	=	17			--------------				2
2	x	+	1	y	+	1	z	=	-4			--------------				3
																
consider equation 1 &2				Eliminate	y											
Add the two																
2	x		+	0	y	+	5	z	=	17	-------------				4	
consider equation 2 & 3				Eliminate	y											
						
Add the two																
3	x	+	0	y	+	5	z	=	13	-------------5				5		
Consider (4) & (5)			Eliminate	x												
Multiply 4 by				-3												
Multiply (5) by				2												
we get																
-6	x	+	-15	z	=	-51										
6	x	+	10	z	=	26										
Add the two																
0	x	+	-5	z	=	-25										
/	-5															
z	=	5														
3	x	+	5	z=	13											
3	x	+	25	=	13											
			x	=	-4											
Plug x & z in eq (1)																
1	x	+	1	y	+	1	z	=	0			--------------				1
	-4	+	1	y	+	5		=	0							
			1	y				=	-1							
				y	=				-1							
	x=	-4	y=	-1	z=	5