The expression is equivalent to -(-x-16), can be found using the simple PEMDAS Rule
As per the Rule
P for parenthesis
E for Exponential
M for Multiplication
D for Division
A for Addition
S for Subtraction
[tex] -(-x-16)=x+16\\
\\
Hence \  the  \ equivalent  \ expression \  is  \ x+16 [/tex]