Answer
$$[x]_S=\left[ \begin {array}{ccc} 2\\ -1\\-1\end {array} \right].$$
Work Step by Step
Since we have
$$x= 2(1,0,0)+0(1,1,0)-(0,1,1)=(2,-1,-1).$$
then we can write $x$ relative to the standard basis of $R^3$ as follows
$$x= (2,-1,-1)=2(1,0,0)-(0,1,0)-(0,0,1) .$$
Thus, the coordinates matrix of $x$ in $R^3$ relative to the
standard basis is
$$[x]_S=\left[ \begin {array}{ccc} 2\\ -1\\-1\end {array} \right].$$
