a(2a-3),a²(1－3a),3x(x²－2x－1),-2x²y(3x²－2

a(2a-3)=2a^2-3a
a²(1－3a)=a^2-3a^3
3x(x²－2x－1)=3x^3-6x^2-3x
-2x²y(3x²－2x－3)=-6x^4y+4x^3y+6x^2y
(2x²－3xy＋4y²)(-2xy)=-4x^3y+6x^2y^2-8xy^3
(-x)³·(-2xy²)³－4xy²(7x的5次方y的4次方－0.5xy³)
=-8x^6y^6-4xy^2(7x^5y^4-0.5xy^3)
=-8x^6y^6-28x^6y^6+2x^2y^5
=2x^2y^5-36x^6y^6
(1)-3a²(a²－2a－3)＋3a(a³－2a²－3a)＋2012,其中a＝2012
=-3a²(a²－2a－3)＋3a^2(a^2－2a－3)+2012
=2012
(2)x的n次方(x的n次方＋9x－12)－3(3x的n＋1次方－4x的n次方),其中x＝-2,n＝3
=x^n(x^n+9x-12)-3[3x^(n+1)-4x^n)
=x^2n+9x^(n+1)-12x^n-9x^(n+1)+12x^n
=x^2n
x＝-2,n＝3
=(-2)^(2*3)
=2^6
=64