1. 小明只抄错了方程1,所以他的解应该满足方程2,代入可得
-b + 3a = 1
同理,把小文的解带入方程1,可得
3a + 2b = 16
联立以上两个方程,解得
a = 2, b = 5,
所以原方程组为
2x + 5y = 16,
5x + 2y = 1,
解得
x = -9/7, y = 26/7 .
2. 解互为相反数,则 x = -y ,带入,得
-3y - 2y = 3m + 1,
-5y + 4y = 8 - m,
整理得
3m - 5y = 1,
m - y = 8,
解得 m = 39/2 = 19.5 .