SOLUTION: X-y=9;x-y+3z=2;4y-3z=5

x -  y      = 9,   (1)
x -  y + 3z = 2,   (2)
    4y - 3z = 5.   (3).

Distract the eq.(1) from the eq.(2).  You will get 

3z = 2-9 = -7  --->  z = .

Then from (3), 4y = 5 + 3z =  = 5-7 = -2  --->  y =  = .

Then from (1), x = 9 + y =  = .

Answer. x = ,  y = ,  z = .