1/(x-2) - 3/(x-1) = (2x+k)/(x-1)(x-2).去分母：x-1 - 3(x-2) = 2x + k移项、合并：4x = 5-k.x = (5-k) /4.当x = 2 时，(5-k) /4 = 2. k = -3.当x = 1 时，(5-k) /4 = 1. k = 1.所以，k ≠ 1，-3 时，原方程有解.
k不等于1或负三时
