题目
当M为何值时,方程组5X+6Y=2m-3,7x-4y=m-2的解满足X小于0,Y大于0
提问时间:2020-10-17
答案
5X+6Y=2m-3 (1)
7x-4y=m-2 (2)
(1)*2+(2)*3
10x+12y+21x-12y=4m-6+3m-6
31x=7m-12
(1)*7-(2)*5
35x+42y-35x+20y=14m-21-5m+10
62y=9m-11
x11/9
所以11/9
7x-4y=m-2 (2)
(1)*2+(2)*3
10x+12y+21x-12y=4m-6+3m-6
31x=7m-12
(1)*7-(2)*5
35x+42y-35x+20y=14m-21-5m+10
62y=9m-11
x11/9
所以11/9
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