1、[2x^2-(x+y)(x-y)][(-x-y)(-x+y)+2y^2]其中x=-1,y=-22、3m(x-y)-n(y-x)3、(3a^3)^3-7a^5[a^4-a(4a^3-1)]以上题目求解答、希望有心人帮忙,并写出过程、在此谢过!
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1、[2x^2-(x+y)(x-y)][(-x-y)(-x+y)+2y^2]其中x=-1,y=-22、3m(x-y)-n(y-x)3、(3a^3)^3-7a^5[a^4-a(4a^3-1)]以上题目求解答、希望有心人帮忙,并写出过程、在此谢过!
1、[2x^2-(x+y)(x-y)][(-x-y)(-x+y)+2y^2]其中x=-1,y=-2
2、3m(x-y)-n(y-x)
3、(3a^3)^3-7a^5[a^4-a(4a^3-1)]
以上题目求解答、希望有心人帮忙,并写出过程、在此谢过!
1、[2x^2-(x+y)(x-y)][(-x-y)(-x+y)+2y^2]其中x=-1,y=-22、3m(x-y)-n(y-x)3、(3a^3)^3-7a^5[a^4-a(4a^3-1)]以上题目求解答、希望有心人帮忙,并写出过程、在此谢过!
1,原式=[2x^2-(x^2-y^2)][(x^2-y^2)+2y^2]
=(x^2+y^2)(x^2-y^2)
=x^4-y^4
=1-16
=-15
2,原式=3m(x-y)+n(x-y)
=(3m+n)(x-y)
3,原式=27a^9-7a^9+7a^6(4a^3-1)
=20a^9+28a^9-7a^6
=48a^9-7a^6
做错一道。。
1.原式=2(x²+ y²)
当x=-1，y=-2时,原式=10
2.3m(x-y)-n(y-x)=3m(x-y) +n(x - y)=(x- y)(3m+n)
3.
1、[2x^2-(x+y)(x-y)][(-x-y)(-x+y)+2y^2]
=(2x^2-x^2+y^2)(x^2-y^2+2y^2)
=(x^2+y^2)^2
=(1+4)^2
=25
2、3m(x-y)-n(y-x)
=3m(x-y)+n(x-y)
=(3m+n)(x-y)
3、(3a^3)^3-7a^5[a^4-a(4a^3-1)]
=27a^9-7a^9+7a^6(4a^3-1)
=20a^9+28a^9-7a^6
=48a^9-7a^6
=a^6(48a^3-7)