Question

1.若m-n=4,mn=1,求（9-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值

Answer 1

1、原式＝9-2mn+2m+3n-3mn-2n+2m-m-4n-mn＝9-6mn+3m-3n＝9-6+12＝15

2、6a^2+9a+5＝(2a^2+3a+1)×3＋2＝6×3＋2＝20

3、[(2a+3b-a+b)+(a+b-a/2+b/2)]×2＝3a+11b