Answer
$10$
Work Step by Step
RECALL:
$-(-a)=a$
AND
$a-b=a+(-b)$
Substitute the given values of the variables to obtain:
$-x-y-z = -(-2)-3-(-11)$
Use the rule above to obtain:
$=2-3-(-11)
\\=(2-3)-(-11)$
Apply the second rule above to the expression inside the parentheses to obtain:
$=[2+(-3)]-(-11)
\\=(-1) - (-11)$
Apply the rule above to obtain:
$=-1+11
\\=10$