$\begin{equation*} \begin{cases} y = 1 - 7x, &\\ 4x - y = 32; & \end{cases} \end{equation*}$
4x − (1 − 7x) = 32
4x − 1 + 7x = 32
11x = 32 + 1
11x = 33
x = 33 : 11
x = 3
y = 1 − 7x = 1 − 7 * 3 = 1 − 21 = −20
Ответ: (3;−20)

$\begin{equation*} \begin{cases} x = y + 2, &\\ 3x - 2y = 9; & \end{cases} \end{equation*}$
3 * (y + 2) − 2y = 9
3y + 6 − 2y = 9
y = 9 − 6
y = 3
x = y + 2 = 3 + 2 = 5
Ответ: (5;3)

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

$\begin{equation*} \begin{cases} x = 2y - 3, &\\ 3x + 2y = 7. & \end{cases} \end{equation*}$
3 * (2y − 3) + 2y = 7
6y − 9 + 2y = 7
8y = 7 + 9
8y = 16
y = 16 : 8
y = 2
x = 2y − 3 = 2 * 2 − 3 = 4 − 3 = 1
Ответ: (1;2)