若把括号里的分开 原式=(x^2-4)[1+1/(x-2)]/(x^2-2x+1) =[(x^2-4)+(x^2-4)/(x-2)]/(x^2-2x+1) =(x^2-4)/(x^2-2x+1)+(x+2)/(x^2-2x+1) 若先算括号 原式=[(x-1)/(x-2)]/(x^2-2x+1)/(x^2-4) =(x-1)(x^2-4)/[(x-2)(x^2-2x+1)] =(x^2+x-2)/(x^2-2x+1) =(x^2-4+x+2)/(x^2-2x+1) =(x^2-4)/(x^2-2x+1)+(x+2)/(x^2-2x+1) 所以两种算法的结果是一样的.
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