Question 558692
2x+y+	z=4--------------1
3x-y+4z	=11--------------2
x-y+5z=	20--------------3
Add the two 																
5x+y+5z	=15	-------------	4	
consider equation 2 & 3				Eliminate y												
Multiply 2 by 				-1												
Multiply 3 by				1												
we get 																
-3x+y-4	z=-11							
x-y+5z	=	-4							
Add the two 																
-2x+z	=	-15	-------------5				5		
Consider (4) & (5)	Eliminate x													
Multiply 4 by				2												
Multiply (5) by				5												
we get				2												
10	x	+	10	z	=	30										
-10	x	+	5	z	=	-75										
Add the two 																
0	x	+	15	z	=	-45										
/	15															
z	=	-3	    												
																
Plug the value of z in						5										
-2	x	+	-3		=	-15										
-2	x	=	-12													
x	=	6	    												
plug value of x & z in					1											
12	+	1	y	+	-3	=	4									
1	y	=	-12	+	3	+	4									
	y=	-5