吉林省七年級數學下冊72二元一次方程組的解法4課件新版華東師大版-閱讀頁
2025-07-03 18:51本頁面
【正文】 2x7y =10, 3x8y 10 = 0. ② ① 解 2x7( ) = 10, 5y = 10, 即 所以 x = 2, y = 2. 2x+14 = 10, 把 y=2代入① ,得 y = 2. (9) 3x8y = 10. 由② ,得 ③ ③ 2,得 ① 3,得 6x16y = 20, 6x21y = 30. ④ ⑤ ④ ⑤ ,得 16y(21y) = 2030, 2 2x = 1014, 2x = 4, x = 2. 消去 x 做一做 :用加減法解方程組 ???????.1123,642)1(yxyx???????.153,732)2(yxyx?????.1,5yx?????.1,2yx?????????.01 0 073,0203)3(yxyx?????.10,10yx(附加題 )
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