−9x+y= \,\,71 71 -x-y= −x−y= \,\,-1 −1 \mathbf{Add}\text{ to eliminate }\mathbf{y.}Add to eliminate y. \mathbf{Subtract}\text{ to eliminate }\mathbf{x.}Subtract to eliminate x. \mathbf{Subtract}\text{ to eliminate }\mathbf{y.}Subtract to eliminate y. \mathbf{Add}\text{ to eliminate }\mathbf{x.}Add to eliminate x.