$\begin{equation*} \begin{cases} 6x + 5y = 1 &\\ 2x - 3y = 33 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 6x + 5y = 1 &\\ 2x = 3y + 33 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 6x + 5y = 1 &\\ x = 1,5y + 16,5 & \end{cases} \end{equation*}$
6x + 5y = 1
6 * (1,5y + 16,5) + 5y = 1
9y + 99 + 5y = 1
14y = 1 − 99
14y = −98
y = −98 : 14
y = −7
x = 1,5y + 16,5 = 1,5 * (−7) + 16,5 = −10,5 + 16,5 = 6
Ответ: (6;−7)

$\begin{equation*} \begin{cases} 5x + 6y = 4 &\\ 3x + 5y = 1 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 5x = 4 - 6y &\\ 3x + 5y = 1 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} x = 0,8 - 1,2y &\\ 3x + 5y = 1 & \end{cases} \end{equation*}$
3x + 5y = 1
3 * (0,8 − 1,2y) + 5y = 1
2,4 − 3,6y + 5y = 1
1,4y = 1 − 2,4
1,4y = −1,4
y = −1
x = 0,8 − 1,2y = 0,8 − 1,2 * (−1) = 0,8 + 1,2 = 2
Ответ: (2;−1)

$\begin{equation*} \begin{cases} 4x - 5y = -2 &\\ 3x + 2y = -13 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 4x - 5y = -2 &\\ 2y = -13 - 3x & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 4x - 5y = -2 &\\ y = -6,5 - 1,5x & \end{cases} \end{equation*}$
4x − 5y = −2
4x − 5 * (−6,5 − 1,5x) = −2
4x + 32,5 + 7,5x = −2
11,5x = −2 − 32,5
11,5x = −34,5
x = −34,5 : 11,5
x = −3
y = −6,5 − 1,5x = −6,5 − 1,5 * (−3) = −6,5 + 4,5 = −2
Ответ: (−3;−2)

$\begin{equation*} \begin{cases} 3x - 7y = 1 &\\ 2x + 3y = 16 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 3x - 7y = 1 &\\ 2x = 16 - 3y & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 3x - 7y = 1 &\\ x = 8 - 1,5y & \end{cases} \end{equation*}$
3x − 7y = 1
3 * (8 − 1,5y) − 7y = 1
24 − 4,5y − 7y = 1
−11,5y = 1 − 24
−11,5y = −23
y = −23 : (−11,5)
y = 2
x = 8 − 1,5y = 8 − 1,5 * 2 = 8 − 3 = 5
Ответ: (5;2)