Given the following system of equations:
[tex]\begin{cases}x+y=2 \\ y=2x+5\end{cases}[/tex]notice that we can substitute the second equation on the first one to get the following:
[tex]\begin{gathered} x+(2x+5)=2 \\ \Rightarrow x+2x=2-5 \\ \Rightarrow3x=-3 \\ \Rightarrow x=\frac{-3}{3}=-1 \\ x=-1 \end{gathered}[/tex]now that we have that x = -1, we can use this value on the first equation to find the value of y:
[tex]\begin{gathered} x=-1 \\ \Rightarrow-1+y=2 \\ \Rightarrow y=2+1=3 \\ y=3 \end{gathered}[/tex]therefore, the solution of the system is (-1,3)
