You are given the system of equations
[tex]\left\{\begin{array}{l}y=2x-1\\5x-4y=1.\end{array}\right.[/tex]
If you want simply to know whether (1,1) is a solution of this system, then substitute x=1 and y=1 into both equations:
[tex]\left\{\begin{array}{l}1=2\cdot 1-1\\5\cdot 1-4\cdot 1=1\end{array}\Rightarrow \begin{array}{l}1=1\\1=1\end{array}\right.[/tex]
This means that (1,1) is a solution, because both iqualities hold.
