$\begin{equation*} \begin{cases} 2 - 3x = 2(1 - y) &\\ 4(x + y) = x - 1,5 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 2 - 3x = 2 - 2y &\\ 4x + 4y = x - 1,5 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} -3x + 2y = 2 - 2 &\\ 4x - x + 4y = -1,5 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} -3x + 2y = 0 &\\ 3x + 4y = -1,5 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 3x = 2y &\\ 3x + 4y = -1,5 & \end{cases} \end{equation*}$
3x + 4y = −1,5
2y + 4y = −1,5
6y = −1,5
y = −1,5 : 6
y = −0,25
3x = 2y
3x = 2 * (−0,25)
3x = −0,5
$x = -\frac{1}{2} : 3$
$x = -\frac{1}{2} * \frac{1}{3}$
$x = -\frac{1}{6}$
Ответ: $(-\frac{1}{6}; -\frac{1}{4})$

$\begin{equation*} \begin{cases} 6x + 3 = 8x - 3(2y - 4) &\\ 2(2x - 3y) - 4x = 2y - 8 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 6x + 3 = 8x - 6y + 12 &\\ 4x - 6y - 4x = 2y - 8 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 6x - 8x + 6y = 12 - 3 &\\ 4x - 6y - 4x - 2y = -8 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} -2x + 6y = 9 &\\ -8y = -8 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} -2x + 6y = 9 &\\ y = 1 & \end{cases} \end{equation*}$
−2x + 6y = 9
−2x + 6 * 1 = 9
−2x = 9 − 6
−2x = 3
x = 3 : (−2)
x = −1,5
Ответ: (−1,5;1)

$\begin{equation*} \begin{cases} 2x - 3(2y + 1) = 15 &\\ 3(x + 1) + 3y = 2y - 2 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 2x - 6y - 3 = 15 &\\ 3x + 3 + 3y = 2y - 2 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 2x - 6y = 15 + 3 &\\ 3x + 3y - 2y = -2 - 3 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 2x - 6y = 18 &\\ 3x + y = -5 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} x - 3y = 9 &\\ y = -5 - 3x & \end{cases} \end{equation*}$
x − 3y = 9
x − 3 * (−5 − 3x) = 9
x + 15 + 9x = 9
10x = 9 − 15
10x = −6
x = −0,6
y = −5 − 3x = −5 − 3 * (−0,6) = −5 + 1,8 = −3,2
Ответ: (−0,6;−3,2)

$\begin{equation*} \begin{cases} 4y + 20 = 2(3x - 4y) - 4 &\\ 16 - (5x + 2y) = 3x - 2y & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 4y + 20 = 6x - 8y - 4 &\\ 16 - 5x - 2y = 3x - 2y & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 4y - 6x + 8y = -4 - 20 &\\ -5x - 2y - 3x + 2y = -16 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 12y - 6x = -24 &\\ -8x = -16 & \end{cases} \end{equation*}$
$\begin{equation*} \begin{cases} 2y - x = -4 &\\ x = 2 & \end{cases} \end{equation*}$
2y − x = −4
2y − 2 = −4
2y = −4 + 2
2y = −2
y = −2 : 2
y = −1
Ответ: (2;−1)