..自学不易..希望达人指教...4x²·(-xy²)³(1.3·10^5)(3.8·10^3)(4a-b²)·(-2b)2x²(x-½)5ab·(2a-b+0.2)(2a²-2/3a-4/9)·(-9a)(x-6)·(x-3)(x+½)·(x-1/3)(3x+2)(x+2)(4y-1)·(y-5

Question

..自学不易..希望达人指教...
4x² · (-xy²)³ (1.3 · 10^5)(3.8 · 10^3)
(4a-b²) · (-2b) 2x²(x- ½)
5ab · (2a-b+0.2) (2a²- 2/3a - 4/9) · (-9a)
(x-6) · (x-3) (x+½) · (x- 1/3)
(3x+2)(x+2) (4y-1) · (y-5)
(x-2)(x²+4) (x-y)(x²+xy+y²)
x²(x-1)-x(x²+x-1) 已知x=½
(x-3)(x-3) · 6(x²+X-1)
(2x+1)²-(x+3)-(x-1)²+!
求运算步骤和结果...
..只是初二上学期的整式乘法....需要题的运算步骤和结果- -

Answer 1

4x² · (-xy²)³ = - 4x^2*x^3*4x^2*y^6=-4x^5*y^6.（幕的运算）
(1.3 · 10^5)(3.8 · 10^3)=(1.3*3.8)*10^(5+3)=4.94*10^8.（幕的运算）
(4a-b²) · (-2b) =-8ab+2b^3
2x²(x- ½)=2x^(2-1/2)=2x^(3/2)
5ab · (2a-b+0.2)=10a^2*b-5ab^2+ab
(2a²- 2/3a - 4/9) · (-9a)=-18a^3+6a^2+4a
(x-6) · (x-3) =x^2-(6+3)x+6*3=x^2-9x+18
(x+½) · (x- 1/3)=x^2+(1/2-1/3)x-1/2*1/3=x^2+1/6x-1/6
(3x+2)(x+2)=3x^2+(2+3*2)x+2*2=3x^2+8x+4
(4y-1) · (y-5)=4y^2-(1+4*5)y+1*5=4y^2-21y+5
(x-2)(x²+4) =x^3-2x^2+4x-8
(x-y)(x²+xy+y²)=x^3+x^2*y+xy^2-x^2y-xy^2+y^3=x^3+y^3
x²(x-1)-x(x²+x-1)=x^3-x^2-x^3-x^2+x=-2x^2+x .
当x=½时,原式=-2*(1/2)^2+1/2=-1/2+1/2=0 （先化简,再求值）
(x-3)(x-3) · 6(x²+X-1)=6(x-3)^2*(x^2+x-1)=6(x^2-6x+9)(x^2+x-1)
=6(x^4+x^3-x^2-6x^3-6x^2+6x+9x^2+9x-9)
=6(x^4-5x^3+2x^2+15x-9)
=6x^4-30x^3+12x^2+90x-54
(2x+1)²-(x+3)-(x-1)²+1=4x^2+4x+1-x-3-x^2+2x-1+1
=3x^2+5x-2