a+b=2,ab=-3,则整式2(a-2b+ab)+(a+7b-3ab)的值是_____________.

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/04 01:41:51

a+b=2,ab=-3,则整式2(a-2b+ab)+(a+7b-3ab)的值是_____________.

2(a-2b+ab)+(a+7b-3ab)
=2a-4b+2ab+a+7b-3ab
=3a+3b-ab
=3(a+b)-ab
=3*2-(-3)
=9

2(a-2b+ab)+(a+7b-3ab)
=2a-4b+2ab+a+7b-3ab
=3a+3b-ab
=2*3+3
=9

2(a-2b+ab)+(a+7b-3ab)
=2a-4b+2ab+a+7b-3ab
=3a+3b-7ab
=3(a+b)-7ab
=6+21
=27

2(a-2b+ab)+(a+7b-3ab)
=2a-4b+2ab+a+7b-3ab
=3a+3b-ab
=3(a+b)-ab
=3×2-(-3)
=9