Question

What is the ordered triple of:

x-2y+3z=-3

2x-3y-z=7

3x+y-2z=6

 

Answer 1

1) x - 2y + 3z = -3

2) 2x - 3y - z = 7

3) 3x + y -2z = 6

multiply eq(3) by 2, add to eq(1):

 x  -  2y  + 3z  =  -3

6x + 2y   -  4z =  12

________________

7x             - z  =  9   (a)

multiply eq(3) by 3, add to eq(2):

2x  -  3y  -  z  =  7

9x  +  3y  - 6z =  18

________________

11x            - 7z  = 25  (b)

multiply eq(a) by -7, add to eq(b):

-49x  + 7z  =  -63

 11x   -  7z  =   25

______________

-38x             =  -38

x = -38/-38 = 1

using eq(a):

7(1) - z = 9

-z = 2

z = -2

using eq(2):

2(1) - 3y - (-2) = 7

2 - 3y + 2 = 7

-3y = 3

y = 3/-3 = -1

check using eq(1):

x - 2y + 3z = -3

1 - 2(-1) + 3(-2) = -3

1 + 2 - 6 = -3

-3 = -3

x = 1, y = -1, z = -2  or  (1, -1, -2)

Answer 2

3x	-	y	-	z	=	3
-2x	+	3y	+	z	=	-3
4x	-	2y	-	2z	=	2

 

Answer 3

 

 

Q. 1	The value of x and y in the system of equations 2x+5y+z=-1,x+7y-6z=-18 and 3y+6z=9  are ___
	A)	(1,2)
	B)	(1,-1)
	C)	(-1,2)
	D)	None of these