习题3(4.) a 5 1 4a 1 已知 b4 1 =1,求 4b 11 =1. c 4 1 4c 1 1 习题4(5.(10 1202 计算 10520 0117 技2消去后展开 口卡日·工4元，Q0 张莉(Tongji University) 线性代数 4/60SK3 (4.) Æ a 5 1 b 4 1 c 4 1  = 1, ¶ 4 a 54 1 4 b 1 1 4 c 1 1  = 1. SK4 (5.(1)) Oé 4 1 2 4 1 2 0 2 10 5 2 0 0 1 1 7  = 0. )Ua21û￾–m. ‹s (Tongji University) Ç 5 ì Í 4 / 60