若a-b=5,ab=-5,求(2a+3b-2ab)-(a+4b+ab)-(3ab-2a+2b)的值

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/03 17:58:39

若a-b=5,ab=-5,求(2a+3b-2ab)-(a+4b+ab)-(3ab-2a+2b)的值
若a-b=5,ab=-5,求(2a+3b-2ab)-(a+4b+ab)-(3ab-2a+2b)的值

若a-b=5,ab=-5,求(2a+3b-2ab)-(a+4b+ab)-(3ab-2a+2b)的值
原式=2a+3b-2ab-a-4b-ab-3ab+2a-2b
=3a-3b-6ab
=3(a-b)-6ab
=15+30
=45

(2a+3b-2ab)-(a+4b+ab)-(3ab-2a+2b)
=2a+3b-2ab-a-4b-ab-3ab+2a-2b
=3a-3b-6ab
=3(a-b)-6ab
=3×5-6×(-5)
=45

原式=2a+3b-2ab-a-4b-ab-3ab+2a-2b
=3a-3b-6ab
=3(a-b)-6ab
=15+30
=45

算错了