Question 536403
21	x	+	-7	y	+	51	z	=	141			--------------				1
13	x	+	9	y		-5	z	=	-19			--------------				2
19	x	+	-8	y	+		23	z	30			--------------				3
																
consider equation 1 &2				Eliminate 	y											
Multiply 1 by							9									
Multiply 2 by							7									
we get																
189	x		+	-63	y	+	459	z	=	1269						
91	x		+	63	y	+	-35	z	=	-133						
Add the two 																
280	x		+	0	y	+	424	z	=	1136	-------------				4	
consider equation 2 & 3				Eliminate 	y											
Multiply 2 by 				8												
Multiply 3 by				9												
we get 																
104	x	+	72	y	+	-40	z	=	-152							
171	x	+	-72	y	+	207	z	=	0							
Add the two 																
275	x	+	0	y	+	167	z	=	-152	-------------5				5		
Consider (4) & (5)			Eliminate 	x												
Multiply 4 by				-275												
Multiply (5) by				280												
we get				2												
-77000	x	+	-116600	z	=	-312400										
77000	x	+	46760	z	=	-42560										
Add the two 																
0	x	+	-69840	z	=	-354960										
/	-69840															
z	=	5.08	OR	5  8/97												
																
Plug the value of 			z	in		(5)										
275	x	+	848.77		=	-152										
275	x	=	-1000.77													
x	=	-3.64	OR	-3 62/97												
plug value of x & z in					1											
-76.42	+	-7	y	+	259.21	=	141									
-7	y	=	76.42	+	-259.21	+	141									
y	=	5.97	OR	6    												
										CHECK
Plug values of x,y,z in (2)						
																
13	-3.64	+	9	5.97		-5	5.08	=	-19							
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