x - 5y - z = 14
(-x) (-x) (subtracting x from both sides)
-5y - z = 14 - x
(+5y) (+5y) (adding 5y to both sides)
-z = 14 - x + 5y
(-z = 14 - x + 5y) * (-1) (multiplying both sides by -1 to make z positive)
z = -14 + x - 5y (Answer :))
