数学之美团为你解答
2/(x-1)
3/(x²-2x+1) = 3/(x-1)²
1/(x²-1) = 1/[(x+1)(x-1)]
所以公分母为 (x+1)(x-1)²
2/(x-1) = 2(x+1)(x-1) / [(x+1)(x-1)²]
3/(x²-2x+1) = 3(x+1) / [(x+1)(x-1)²]
1/(x²-1) = (x-1) / [(x+1)(x-1)²]