1.已知,a²-4ab=2,3ab+b的平方=7.求整式3a²+4b的平方的值
2.已知a-b=5,ab=1,求(2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)的值
要有过程!!谢谢
1.已知,a²-4ab=2,3ab+b的平方=7.求整式3a²+4b的平方的值
2.已知a-b=5,ab=1,求(2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)的值
要有过程!!谢谢
1.依题意,得:a²-4ab=2①
3ab+b²=7②
①×3,得:3a²-12ab=6③
②×4,得:12ab+4b²=28④
③+④,得:3a²+4b²=34
2.(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
=3×5-6×1
=15-6
=9
1.依题意,得:a²-4ab=2①
3ab+b²=7②
①×3,得:3a²-12ab=6③
②×4,得:12ab+4b²=28④
③+④,得:3a²+4b²=34
2.(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 =3×5-6×1 =15-6 =9