Ответ:

1) а) B, C, N

б) A, K, D, M

2) 2/3AC + 5 = AC

2/3AC - AC = -5

1/3AC = 5

AC = 15

AB = 2/3*15 = 10

3) AB = 2x

BC = 3x

AC = AB+BC

2x+3x = 10

5x = 10

x = 2

AB = 2*2 = 4

BC = 3*2 = 6