3 m=5 3 n=7 3 n+m= 3 3n-2n=3 m=5 3 n=7 3 n+m= 3 3n-2n=

问题描述:

3 m=5 3 n=7 3 n+m= 3 3n-2n=
3 m=5
3 n=7
3 n+m=
3 3n-2n=

3(n+m)=12
3(3n-2n)=7

n + m = 5 + 7 = 12
3n - 2n = 15 - 14 = 1