【正文】
指出 三對(duì)數(shù)值分別是下面哪一 個(gè)方程組的解 . x =1, y = 2, x = 2, y = 2, x = 1, y = 2, ① ② ③ y + 2x = 0 x + 2y = 3 x – y = 4 x + y = 0 y = 2x x + y = 3 解: ① ( )是方程組( )的解; ② ( )是方程組( )的解; ③ ( )是方程組( )的解; x =1, y = 2, y = 2x x + y = 3 x = 2, y = 2, x – y = 4 x + y = 0 x = 1, y = 2, y + 2x = 0 x + 2y = 3 口 答 題 若 是關(guān)于 x、 y