已知a-b=4,ab=1,则(2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)=_.
问题描述:
已知a-b=4,ab=1,则(2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)=______.
答
∵a-b=4,ab=1
∴(2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)
=2a+3b-2ab-a-4b-ab-3ab-2b+2a
=3a-3b-6ab
=3(a-b)-6ab
=3×4-6×1
=6.