Question

$3(x - y) = 6(y + 1) \\ \frac{x}{3} - 1 \frac{1}{3} = y$

Answer 1

$\begin{cases}3(x - y) = 6(y + 1)\\ \frac{x}{3} - 1 \frac{1}{3} = y\end{cases}$

$\begin{cases}3x -3 y = 6y + 6\\ \frac{x}{3} - \frac{4}{3} = y\ /\cdot3\end{cases}$

$\begin{cases}3x -3 y -6y = 6\\ x - 4 = 3y\end{cases}$

$\begin{cases}3x -9y = 6\\ x -3y= 4\ /\cdot(-3)\end{cases}$

$\begin{cases}3x -9y = 6\\ -3x+9y=-12\end{cases}$

+______________

$0=-6$