5x^4+(3x^2y-10)-(3x^2y-x^4+1)

5x^4+(3x^2y-10)-(3x^2y-x^4+1)
=5x^4+3x^2y-10-3x^2y+x^4-1
=6x^4-11

2a^2-[1/2(ab+a^2)+8ab]
=2a^2-1/2(ab+a^2)-8ab
=2a^2-1/2ab-1/2a^2-8ab
=3/2a^2-17/2ab

1/4(-4x^2+2x-8)-1/2(x-2),其中x=1/2
=-x^2+1/2x-2-1/2x+1
=-x^2-1
=-1/4-1
=-5/4

2（a^2b+ab^2)-[2(a^2b-1)+2ab^2]-2ab 其中a=-2 b=2
=2a^2b+2ab^2-2(a^2b-1)-2ab^2-2ab
=2a^2b+2ab^2-2a^2b+2-2ab^2-2ab
=2-2ab
=2-2*(-2)*2
=10

有一根竹竿长a米，一天绳子长（a+ab）米（b大于1/2a）将绳子对折后，它比竹竿长多少米？
1/2(a+ab)-a
=1/2a+1/2ab-a
=1/2(ab-a)米

132132132

哇，这么复杂啊