题目下列每对数值中,是方程x−3y=1x-3y=1x−3y=1的解的是（ ）A.{x=2y=1\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.{x=2y=1B.{x=2y=−1\left\{\begin{array}{l}{x=2}\\{y=-1}\end{array}\right.{x=2y=−1C.{x=−2y=1\left\{\begin{array}{l}{x=-2}\\{y=1}\end{array}\right.{x=−2y=1D.{x=−2y=−1\left\{\begin{array}{l}{x=-2}\\{y=-1}\end{array}\right.{x=−2y=−1知识点：解二元一次方程组——代入消元法章节：方程与不等式 / 二元一次方程组
