几道数学题,化简.
问题描述：
几道数学题,化简.
3a^b-[2ab-2(a^2b+2ab^2)]
x(-6x-9)-x(-8x-15)+2X(3-X)
7X^3Y^2/[(-7X^5Y^3)/(-1/3X^3Y^2)]
答
3a^b-[2ab-2(a^2b+2ab^2)]=3a²b-（2ab-2a²b-2ab²)=3a²b-2ab+2a²b+2ab²=5a²b+2ab²-2abx(-6x-9)-x(-8x-15)+2X(3-X)=-6x²-9x+8x²+15x+6x-2x²=12x7X^3Y^2/[(-7X...你和楼下答案不一样。。。。第三题答案为1/3xy