Question

证明多项式16+ a-{8a-[a-9-3(1-2a)]}的值与字母a的取值无关

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Answer 1

16+ a-{8a-[a-9-3(1-2a)]}
=16+ a-8a+[a-9-3(1-2a)]
=16-7a+a-9-3(1-2a)
=7-6a-9-3+6a
=-5
所以值与字母a的取值无关

Answer 2

1、
A+B-3C
=(5a^4-5a²b²+2a²b²-b^4)+(a^4+5a²b²-6ab³-2b^4)-3(2a^4-a²b²-b^4)
=5a^4-5a²b²+2a²b²-b^4+a^4+5a²b²-6ab³-2b^4-6a^4+3a²b²+3b^4
=5a²b²-6ab³
=5*1*1/4-6*(-1)*1/8
=5/4+3/4
=2

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
=3×2-6×(-3)
=6+18
=24