۷) $\begin{cases} 5x - y = 11 \\ -3x + 2y = -8 \end{cases} \xrightarrow{x2} \begin{cases} 10x - 2y = 22 \\ -3x + 2y = -8 \end{cases} \to 7x = 14 \to x = 2 \to [2, -1]$

۸) $\begin{cases} x - 3y = 7 \to x = 7 + 3y \\ -2x + y = -4 \end{cases} \to -2(7 + 3y) + y = -4 \to -14 - 6y + y = -4 \to -5y = 10 \to y = -2 \to [1, -2]$

۹) $\begin{cases} 3y - 6x = 2 \\ 2y = -3x + 14 \to 2y + 3x = 14 \end{cases} \to \begin{cases} 3y - 6x = 2 \\ 6y + 9x = 42 \end{cases} \to 9y = 44 \to y = 44/9 \to [34/18, 44/9]$

۱۰) $\begin{cases} 2x - y = 7 \to 2x - y = 7 \xrightarrow{x=2} 4 - y = 7 \to -y = 3 \to y = -3 \\ 3x = 3 - y \to 3x + y = 3 \end{cases} \to 5x = 10 \to x = 2 \to [2, -3]$