先化简,再求当x=913时的值.(x-2)(x2-2x+4)-x(x+3)(x-3)+(2x-1)2.
题型:解答题难度:一般来源:不详
先化简,再求当x=时的值.(x-2)(x2-2x+4)-x(x+3)(x-3)+(2x-1)2. |
答案
原式=(x3-2x2+4x-2x2+4x-8)-x(x2-9)+(4x2-4x+1), =(x3-4x2+8x-8)-(x3-9x)+(4x2-4x+1), =13x-7=9-7=2. 故答案为2. |
举一反三
化简: (1)(2x-y+z-2c+m)(m+y-2x-2c-z); (2)(a+3b)(a2-3ab+9b2)-(a-3b)(a2+3ab+9b2); (3)(x+y)2(y+z-x)(z+x-y)+(x-y)2(x+y+z)(x+y-z). |
若ab2=-6,则-ab(a2b5-ab3-b)的值为______. |
计算: (1)(a-2b+c)(a+2b-c)-(a+2b+c)2; (2)(x+y)4(x-y)4; (3)(a+b+c)(a2+b2+c2-ab-ac-bc). |
已知z2=x2+y2,化简(x+y+z)(x-y+z)(-x+y+z)(x+y-z). |
(1)-3x2y2•(-2xy)2. (2)(a-2b)2+(a+2b)(a-2b) |
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