初二数学因式分解题
1.ab^2-ac^2+4ac-4a 2.a^2+b^2-a^2b^2-4ab-1 3.27x^3+9x^2+3x-1
1.ab^2-ac^2+4ac-4a =a(b^2-c^2+4c-4) =a[b^2-(c-2)^2] =a(b+c-2)(b-c+2) 2.a^2+b^2-a^2b^2-4ab-1 =(a^2-2ab+b^2)-a^2b^2-2ab-1 =(a-b)^2-(ab+1)^2 =(ab+a-b+1)(-ab+a-b-1) 3.27x^3+9x^2+3x-1 题抄错了吧? 1)如果是27x^3+9x^2+3x+1 =9x^2(3x+1)+3x+1 =(3x+1)(9x^2+1) 2)如果是-27x^3+9x^2+3x-1 =(3x-1)(-9x^2+1) =(3x-1)(-3x+1)(3x+1) =-[(3x-1)^2](3x+1)
你第七题怎么写的?
1.ab^2-ac^2+4ac-4a=a(b^2-(c-2)^2)=a(b-c+2)(b+c-2) 2.a^2+b^2-a^2b^2-4ab-1 =(a+b)^2-(ab-1)^2=(a+b-ab+1)(a+b+ab-1) 3.27x^3+9x^2+3x-1 =(3x+1)^3
1.a(b^2-c^2+4c-4) =a[b^2-(c-2)^2] =a(b+c-2)(b-c+2) 2.(a^2+b^2-2ab)-(a^2b^2+2ab+1) =(a+b)^2-(ab+1)^2 =(a+b-ab-1)(a+b+ab+1) 3.似乎无法分解 因为最后是-1而不是+1 不然的话就可以是立方了。
这么简单也不会? 我今年也读初二 我
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