因式分解:x^4-1=(x-1)(x+1)(x^2+1)x^2-2xy+y^2-9=(x-y)^2-9=(x-y-3)(x-y+3)X^2-x-12=(x-4)(x+3)a^5+2a^4b+a^3b^2=a^3(a^2+2ab+b^2)=a^3(a+b)^2
- -直接去买本练习题,上面都有
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