[tex]\bf \begin{cases}
2x+2y=10\\
-x+y=1
\end{cases}\\\\
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-x+y=1\implies y=1+x\impliedby \textit{let's plug that in the first equation}
\\\\\\
2x+2(\stackrel{y}{1+x})=10\implies 2x+2+2x=10\implies 4x=8
\\\\\\
x=\cfrac{8}{4}\implies \boxed{x=2}\impliedby \textit{let's plug that in the second one}
\\\\\\
-(\stackrel{x}{2})+y=1\implies \boxed{y=3}[/tex]
