Suppose that $S=\set{\colvector{2\\-1\\3\\4},\,\colvector{3\\2\\-2\\1}}$. Let $W=\spn{S}$ and let $\vect{x}=\colvector{5\\8\\-12\\-5}$. Is $\vect{x}\in W$? If so, provide an explicit linear combination that demonstrates this.