Question 238270
first, eliminate y from the 1st and 2nd equation:
x - y + z  = -1
x + y + 3z = -3
--------------- (+)
2x + 4z = -4
divide both sides by 2:
x + 2z = -2


then, eliminate y from the 1st and 3rd equation:
 x - y + z  = -1
2x - y + 2z =  0
----------------- (-)
-x - z = -1 
multiply both sides by (-1)
x + z = 1


then, eliminate x from both results:
x + 2z = -2
x +  z =  1
------------ (-)
z = -3


subtitute z = -3 into x + z = 1
x + (-3) = 1
x = 1 + 3 = 4


substitute x = 4 and z = -3 into the 1st equation:
x - y + z = -1
4 - y + (-3) = -1
1 - y = -1
1 + 1 = y
2 = y


so,the result will be: x = 4, y = 2, z = -3