Question

Решите методом сложения.
$(x - 2y = 3 \ (5x + y = 4$
​

Answer 1

Ответ:

x = 1

y = -1

Объяснение:

$begin{equation*}A = left(begin{array}{ccc}1 & -2 &: 3\5 & 1 &: 4\end{array}right)end{equation*}$

$begin{equation*}A = left(begin{array}{ccc}1 & -2 &: 3\10 & 2 &: 8\end{array}right)end{equation*}$

$begin{equation*}A = left(begin{array}{ccc}1+10 & -2+2 &: 3+8\10 & 2 &: 8\end{array}right) = left(begin{array}{ccc}11 & 0 &: 11\10 & 2 &: 8\end{array}right) = left(begin{array}{ccc}1 & 0 &: 1\10 & 2 &: 8\end{array}right)end{equation*}$

$begin{equation*}A = left(begin{array}{ccc}1 & 0 &: 1\5 & 1 &: 4\end{array}right)end{equation*}$

1 * x + 0 * y = 1

5 * x + 1 * y = 4

x = 1 / 1 = 1

5 * 1 + 1 * y = 4

y = [4 - 5x]/1 = 4 - 5 =  -1