先化简再求值x(-6x-9)-x(-8x-15)+2x(3-x)其中x=-1/6 -3a(1/3a^2b-2a)-2a^2(ab+3)其中a=1/3 ,b=-9还有两道-3/2X(1-x+4x^2-2x^4)(2/3ab^2-ab+3/4b)×(-1/2ab)
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![先化简再求值x(-6x-9)-x(-8x-15)+2x(3-x)其中x=-1/6 -3a(1/3a^2b-2a)-2a^2(ab+3)其中a=1/3 ,b=-9还有两道-3/2X(1-x+4x^2-2x^4)(2/3ab^2-ab+3/4b)×(-1/2ab)](/uploads/image/z/1986497-17-7.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BCx%28-6x-9%29-x%28-8x-15%29%2B2x%283-x%29%E5%85%B6%E4%B8%ADx%3D-1%2F6+-3a%EF%BC%881%2F3a%5E2b-2a%29-2a%5E2%28ab%2B3%29%E5%85%B6%E4%B8%ADa%3D1%2F3+%2Cb%3D-9%E8%BF%98%E6%9C%89%E4%B8%A4%E9%81%93-3%2F2X%281-x%2B4x%5E2-2x%5E4%29%282%2F3ab%5E2-ab%2B3%2F4b%29%C3%97%28-1%2F2ab%29)
先化简再求值x(-6x-9)-x(-8x-15)+2x(3-x)其中x=-1/6 -3a(1/3a^2b-2a)-2a^2(ab+3)其中a=1/3 ,b=-9还有两道-3/2X(1-x+4x^2-2x^4)(2/3ab^2-ab+3/4b)×(-1/2ab)
先化简再求值x(-6x-9)-x(-8x-15)+2x(3-x)其中x=-1/6 -3a(1/3a^2b-2a)-2a^2(ab+3)其中a=1/3 ,b=-9
还有两道-3/2X(1-x+4x^2-2x^4)
(2/3ab^2-ab+3/4b)×(-1/2ab)
先化简再求值x(-6x-9)-x(-8x-15)+2x(3-x)其中x=-1/6 -3a(1/3a^2b-2a)-2a^2(ab+3)其中a=1/3 ,b=-9还有两道-3/2X(1-x+4x^2-2x^4)(2/3ab^2-ab+3/4b)×(-1/2ab)
x(-6x-9)-x(-8x-15)+2x(3-x)其中x=-1/6
原式=-6x²-9x+8x²+15x+6x-2x²
=12x
=12×(-1/6)
=-2
-3a(1/3a^2b-2a)-2a^2(ab+3)其中a=1/3 ,b=-9
原式=-a³b+6a²-2a³b-6a²
=-3a³b
=-3×(1/3)³(-9)
=1
-3/2X(1-x+4x^2-2x^4)
=3/2 ×(2x^4-4x^2+x-1)
=3×(x^4 -2x^2 + x/2 -1/2)
=3×[(x²-1)² +x/2 -5/2]
(2/3ab^2-ab+3/4b)×(-1/2ab)
=(-1/2)(ab²)(2ab/3 -a +3/4 )
1、=x(-6x-9+8x+15+6-2x)=12x=-2
剩下的题目能把括号带全?