Question 298286
x + 2y + 3z = 7 -- (1)
-x + 2y -z = 1 -- (2)
-x + y -2z = -2 -- (3)

Adding (1) to (2) yields:

4y + 2z = 8 or simply 2y + z = 4 -- (4)

then adding (1) to (3) yields:

3y + z = 5 -- (5)

so if we make (5) minus (4) that would give us:

y = 1, then using this value in (4) gives z = 2 and finally using these 2 values in (1) gives x = -1

so x = -1, y =1 and z = 2