$3-3=0$  $3\cdot3-2\cdot1=9-2=7$ 
Which of the following is a solution of $$\begin{cases}x-3=0 \textbackslash\textbackslash{} 3x-2y=7 \end{cases}$$? 

[1] ($x$,$y$)=($3$,$-1$) 
[2] ($x$,$y$)=($3$,$1$) 
[3] ($x$,$y$)=($-3$,$1$) 
[4] ($x$,$y$)=($-3$,$-1$) 