Question

2+2=?????????????????

Answer 1

Ответ:

$\begin{cases}3u - v = 8 \\ 7u - 2u = 23 \end{cases} \\ \begin{cases}3u - v = 8 \\ 5u = 23 \end{cases} \\ \begin{cases}3u - v = 8 \\ u = \frac{23}{5} = 4.6 \end{cases} \\ 3 \times \frac{23}{5} - v = 8 \\ \frac{3}{1} \times \frac{23}{5} - v = 8 \\ \frac{69}{5} - v = 8 \\ v = \frac{69}{5} - 8 \\ v = \frac{69}{5} - \frac{40}{5} \\ v = \frac{29}{5} = 5.8 \\ \text{Ответ:\:}(v; u) = (5.8;4.6)$

$\begin{cases} v + 2u =5 \\ u + 2v = 1 \end{cases} \\ \begin{cases}v = 5 - 2u \\ u + 2v = 1 \end{cases} \\ u + 2(5 - 2u) = 1 \\ u + 10 - 4u = 1 \\ - 3u + 10 = 1 \\ - 3u = - 9 \\ u = 3 \\ v = 5 - 2 \times 3 \\ v = 5 - 6 \\ v = - 1 \\ \text{Ответ:\:}(v; u)=(-1; 3)$