[tex]a)\\\\\begin{cases}2x=3(1-y)+2y\\3(y-x)=y-1 \end{cases}\\\\\begin{cases}2x=3-3y +2y\\3 y-3x =y-1 \end{cases}\\\\\begin{cases}2x=3-y\\3 y-3x-y=-1 \end{cases}\\\\\begin{cases}2x+y=3\ \ |*(-2)\\2y-3x=-1 \end{cases}\\\\\begin{cases}-4x-2y=-6\\ -3x+2y=-1 \end{cases}\\+----------\\-7x=-7\ \ |:(-7)\\\\x=1[/tex]
[tex]3(y-x)=y-1 \\3(y-1)=y-1 \\3y-3 =y-1 \\3y-y=-1+3\\2y=2\ \ |:2\\y=1\\\\\begin{cases}x=1\\y=1 \end{cases}[/tex]
[tex]c)\\\\\begin{cases} y=\frac{1}{3}(x-1)\ \ |*3\\3(x+1)=-(y+1) \end{cases}\\\\ \begin{cases} 3y= x-1 \\3 x+3=- y-1\end{cases}\\\\ \begin{cases}-x+ 3y= -1\ \ |*3 \\3 x +y= -1-3\end{cases}\\\\\begin{cases}-3x+ 9y= -3 \\3 x +y= -4\end{cases}\\+---------\\10y=-7\ \ |:10\\\\y=-\frac{7}{10}[/tex]
[tex]3y=x-1\\x=3y+1\\\\x=3*(-\frac{7}{10})+1=-\frac{21}{10}+\frac{10}{10}=-\frac{11}{10}\\\\\begin{cases}x=-\frac{11}{10}\\y=-\frac{7}{10} \end{}[/tex]
