Question

x - y - z = -1
-x + y + y = 1
x + y - z = 1

Answer 1

hello : 
X - y - z = -1   ...(1)
-x + y + z = 1   ...(2)
x + y - z = 1   ...(3)
(2) +(3) : 2y = 2       y = 1
subsct in (1) and (2) :    x - z =0
                                      -x +z = 0
so x = z  the solution has form : (x , 1 , x )     .... x  in R