## Elementary Algebra

$= -17$
1. We first substitute the $x, y, and \space z$ values into the equation using parenthesis: $x - y - z$ for $x = -15$, $y = 12$, $z = -10$ $= (-15) - (12) - (-10)$ 2. 2. A double negative such as "−(−10)" will cancel out to become "10", a positive number. $= - 15 - 12 + 10$ $= -27 + 10$ $= -17$