3m-4n=7 9m-10n+25=0 解m和n得几

2025-12-16 21:42:36
推荐回答(1个)
回答1:

3m-4n=7①
9m-10n+25=0②
①×3-②
-12n+10n-25=21
-2n=46
n=-23
代n=-23入①
3m-4×(-23)=7
3m=-85
m=-85/3
即:m=-85/3,n=-23