51问答网 > 已知a-b=5,ab=-1,求代数式2a-{b-[3a+(4ab-3b)]-a}-2(b-ab)的值.

已知a-b=5,ab=-1,求代数式2a-{b-[3a+(4ab-3b)]-a}-2(b-ab)的值.

2024-12-28 06:37:50

推荐回答（6个）

回答1：

2a-{b-[3a+(4ab-3b)]-a}-2(b-ab)
=2a-b+(3a+4ab-3b)+a-2b+2ab
=2a-b+3a+4ab-3b+a-2b+2ab
=6a--6b+6ab
=6(a-b+ab)
=6(5-1)
=24

回答2：

2a-{b-[3a+(4ab-3b)]-a}-2(b-ab)
=2a-{b-[3a+4ab-3b]-a}-2b+2ab
=2a-{b-3a-4ab+3b-a}-2b+2ab
=2a-{4b-4a-4ab}-2b+2ab
=2a-4b+4a+4ab-2b+2ab
=6a-6b+2ab
=6(a-b)+2ab
=6*5+2*(-1)
=28

回答3：

2a-{b-[3a+(4ab-3b)]-a}-2(b-ab)
=2a-b+(3a+4ab-3b)+a-2b+2ab
=2a-b+3a+4ab-3b+a-2b+2ab
=6a--6b+6ab
=6(a-b+ab) 已知a-b=5,ab=-1
=6(5-1)
=6*4
=24

回答4：

2a-{b-[3a+(4ab-3b)]-a}-2(b-ab)
=2a-[b-(3a+4ab-3b)-a]-2b+2ab
=2a-(b-3a-4ab+3b-a)-2b+2ab
=2a-b+3a+4ab-3b+a-2b+2ab
=6a-6b+6ab
=6(a-b)+6ab
=6*5-6
=24

回答5：

2a-{b-[3a+(4ab-3b)]-a}-2(b-ab)=2a-b+3a+4ab-3b+a-2b+2ab=6a-6b+6ab=6(a-b)+6ab=6*5-6=24

回答6：

原式=2a-(4b-4a-4ab)-2b+2ab
=6a-4b+4ab-2b+2ab
=6a-6b+6ab
=6（a-b)+6ab
=6-6=0