n/(m-2)=2.1
2m+3n=12.2
由1式得
n=2m-4.3
将3式代入2式得
2m+3(2m-4)=12
2m+6m-12=12
8m=24
m=3
n=2m-4
n=2*3-4
n=6-4
n=2