初一数学12道计算题(过程)

1.(2a^2b)·(-1/2ab^2)^3
=2a^2b*(-1/8)a^3b^6
=-(1/4)a^5b^7

2.(-2/5xy^2z)·(-1/2y^2z^2)
=(1/5)xy^4z^3

3.(2x)^3·y^3÷(16xy^2)
=8x^3y^3/16xy^2
=(1/2)x^2y

4.(-a^2b)^4÷(-1/2ab^2)
=a^8b^4/(-1/2ab^2)
=-(1/2)a^7b^2

5.-2x^2y(3xy^2z-2y^2z)
=-6x^3y^3z+4x^2y^3z

6.(-2/3a)(1/2a^2+1/6a+1/4)
=-(1/3)a^3-(1/9)a^2-(1/6)a

7.(x-3y)(x-1/2y)
=x^2+(7/2)xy+(3/2)y^2

8.(-a-3b)(7a+2b)
=-7a^2-2ab-21ab-6b^2
=-7a^2-23ab-6b^2

9.(9x-2y)(x+y)
=9x^2-2xy+9xy-2y^2
=9x^2+7xy-2y^2

10.(-1/3p+1/2p)(-2/3p-1/4p)
=(2/9)p^2+(1/12)pq-(1/3)pq-(1/8)q^2
=(2/9)p^2-(1/4)pq-(1/8)q^2

11.(-1/5a^3x^4-9/10a^2x^3)÷(-3/5ax^2)
=(1/3)a^2x^2+(3/2)ax

12.(-2πr^2h+3πrh^2)÷(1/2πrh)
=-4r+6h

1. (-1/4)a^5b^7
2.(1/5)xy^4z^3
3.(1/2)x^2y
4.2a^7b^2
5.-6x^3y^3z+6x^2y^3z
6.(-1/3)a^3-1/9a^2-1/6a
7.x^2+3/2y^