![3a=3*(4;-4;2)=(3*4;3*(-4);3*2)=(12;-12;6);](https://tex.z-dn.net/?f=3a%3D3%2A%284%3B-4%3B2%29%3D%283%2A4%3B3%2A%28-4%29%3B3%2A2%29%3D%2812%3B-12%3B6%29%3B)
|3a|= ![\sqrt{12^2+(-12)^2+6^2}=18](https://tex.z-dn.net/?f=%5Csqrt%7B12%5E2%2B%28-12%29%5E2%2B6%5E2%7D%3D18)
ответ модуль вектора 3а 18
40m + 3n = 13
20m - 7n = - 5
Решение
- 40m + 14n = 10
17n = 23
n = 23/17 = 1 6/17
20m - 7•( 23/17 ) = - 5
20m = - 5 + ( 161/17 )
20m = - 5 + 9 8/17
20m = 4 8/17
m = 76/17 : 20
m = 38/170
Второй вариант в виде десятичной дроби