Ответ:

c = a + b

c (0 + 6; 2 + 4; 1 - 3); c (6;6;2)

d = 2a - b

d (2*0 - 6; 2*2 - 4; 2*1 - 3); d (-6;0;-1)

|a + b| = √(6²+6²+2²) = √(36 + 36 + 4) = √74

|m| = 3|a|

|a| = √13

|m| = 3√13

m (0*3;2*3;-3*3); m(0;6;-9)