解方程二元一次方程的步骤

①年㈣个季节 2023-03-19 05:10

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  ≡VIP≡

  2023-03-19 06:01

  有两种方法：代入消元法和加减消元法.例：解方程组 x+y = 3 ,2x + 3y = 7解法一：代入消元法x+y = 3 ①2x+3y = 7 ②由①得 y = 3 - x ③代入②得 2x+ 3(3-x) = 7- x + 9 = 7x = 2代入③得 y = 3-2 = 1∴x=2,y=1解法二：加减消元法x+y = 3 ①2x+3y = 7 ②①×2 得2x + 2y = 6 ③② - ③ 得 (2x+3y) - (2x+2y) = 7 - 6y = 1代入①得 x+1=3,x=2∴x=2,y=1
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