3 кг 200 г =3200 г
1) 3200*5/2=8000 г=8 кг масса лебедя
2) 8000/32*3=750г масса чайки
3) 750/5*3=450г масса утки
A(1; 2; -3)
b = (-2; 1; 1)
1)
a - b : (3; 1; -4)
2b: (-4; 2; 2)
![c = \left|\begin{array}{ccc}i&j&k\\3&1&-4\\-4&2&2\end{array}\right|=2i+16j+6k+4k+8i-6j=10i+10j+10k](https://tex.z-dn.net/?f=c+%3D+++%5Cleft%7C%5Cbegin%7Barray%7D%7Bccc%7Di%26j%26k%5C%5C3%261%26-4%5C%5C-4%262%262%5Cend%7Barray%7D%5Cright%7C%3D2i%2B16j%2B6k%2B4k%2B8i-6j%3D10i%2B10j%2B10k)
c = (10; 10; 10)
2) |c| = √(10² + 10² + 10²) = 10√3
3)
a + 2b : (-3; 4; -1)
3a - b = (3; 6; -9) - (-2; 1; 1) = (5; 5; -8)
(a+2b)*(3a-b) =
![\left|\begin{array}{ccc}i&j&k\\-3&4&-1\\5&5&-8\end{array}\right|=-32i-5j-15k-20k+5i-24j=\\=-27i-29j-35k](https://tex.z-dn.net/?f=++%5Cleft%7C%5Cbegin%7Barray%7D%7Bccc%7Di%26j%26k%5C%5C-3%264%26-1%5C%5C5%265%26-8%5Cend%7Barray%7D%5Cright%7C%3D-32i-5j-15k-20k%2B5i-24j%3D%5C%5C%3D-27i-29j-35k)
Число и запятая пример : 1,9998888
29а-32,99=11,09
29а=11,09+32,99
29а=44,08
а=44,08:29
а=1,52
8 др + 6 др +16 дм =30 дм