AB = OB - OA = (4-k, -7)BC = OC - OB = (6, k-5)因 A,B,C 三点虚滑共线,即AB 与 BC 共线有世袜 AB×BC = 0i + 0j + (-k^2+9k+22)k = 0即 k^2 - 9k - 22 =0解差返腊得 k = 11, k = -2