4a-3b=m ①
3a-2b=n, ②
由①×2-②×3得
-a=2m-3n
a=3n-2m
代入②得
3(3n-2m)-2b=n
9n-6m-2b=n
8n-6m-2b=0
得 b=4n-3m

所以14a-2b
=14(3n-2m)-2(4n-3m)
=42n-28m-8n+6m
=34n-22m

答案：34n-22m