求值a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b-2a^4+b^4其中=-2,b=-1

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求值a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b-2a^4+b^4其中=-2,b=-1求值a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b-2a

求值a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b-2a^4+b^4其中=-2,b=-1
求值a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b-2a^4+b^4其中=-2,b=-1

求值a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b-2a^4+b^4其中=-2,b=-1
a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b-2a^4+b^4
=-a^4+7ab-6a^2b^2-3ab^2-a^2b+b^4
先把b=-1代入
=-a^4-7a-6a^2-3a+a^2+1
=-a^4-10a-5a^2+1
=-(-2)^4-10*(-2)-5*(-2)^2+1
=16+20-20+1
=17

a^4+3ab-6a^2b^2-3ab^2+4ab+6a^2b-7a^2b^2-2a^4
=-a^4+7ab-13a^2b^2-3ab^2+6a^2b
b=1
所以原式=-a^4+7a-13a^2-3a+6a^2
=-a^4-7a^2+4a
=-(-2)^4-7*(-2)^2+4*(-2)
=-16-28-8
=-52