If $x=2018$, then the expression $x^{2}+2 x-x(x+1)$ equals
(A) -2018
(B) 2018
(C) 10090
(D) -10090
(E) 4039
For any value of $x$, we have $x^{2}+2 x-x(x+1)=x^{2}+2 x-x^{2}-x=x$.

When $x=2018$, the value of this expression is thus 2018 .

ANsWER: (B)