Answer
$=1 $
Work Step by Step
1. We first substitute the $x, y, and \space z$ values into the equation using parenthesis:
$-x-y+z$ for $x = -8$, $y = -7$, $z = -14$
$= -(-8) - (-7) + (-14)$
2. A double negative such as "$-(-8)$" will cancel out to become "$8$", a positive number. A positive and a negative number like "$+(-14)$" will become "$-14$", a negative number :
$= 8 + 7 - 14$
$= 15 - 14$
$= 1$