It is known that: as shown in Figure 1, M is a certain point on the fixed length line AB, C and D respectively start from m and B and move to the left along the straight line BA at the speed of 1cm / s and 3cm / s, and the direction of motion is shown by the arrow (C is on the line am, D is on the line BM) (1) If AB = 10cm, when points c and d move for 2S, find the value of AC + MD. (2) if points c and d move, there is always MD = 3aC, fill in the blank directly: am=______ Ab. (3) under the condition of (2), where n is a point on the line AB and an-bn = Mn, the value of mnab is obtained

It is known that: as shown in Figure 1, M is a certain point on the fixed length line AB, C and D respectively start from m and B and move to the left along the straight line BA at the speed of 1cm / s and 3cm / s, and the direction of motion is shown by the arrow (C is on the line am, D is on the line BM) (1) If AB = 10cm, when points c and d move for 2S, find the value of AC + MD. (2) if points c and d move, there is always MD = 3aC, fill in the blank directly: am=______ Ab. (3) under the condition of (2), where n is a point on the line AB and an-bn = Mn, the value of mnab is obtained

(1) When points c and d move for 2S, CM = 2cm, BD = 6cm ∵ AB = 10cm, CM = 2cm, BD = 6cm ∵ AC + MD = ab-cm-bd = 10-2-6 = 2cm (2) 14 (3) when point n is on line AB, as shown in the figure ∵ an-bn = Mn, and ∵ an-am = Mn ∵ BN = am = 14ab, ∵ Mn = 12ab, that is mnab = 12. When point n is on the extension line of line AB, as shown in the figure ∵ an-bn = Mn, and ∵ an-bn = ab ∵ Mn = AB, that is mnab = 1