[tex]\overbar{xy}=?\\
\\x+y=10\\
\\ \overbar{xy}-\overbar{yx}=36\\
\\ (10x+y)-(10y+x)=36\\
\\ 10x+y-10y-x=36\\
\\ 9x-9y=36\\
\\ x-y=36:9\\
\\ x-y=4 \Rightarrow x=4+y\\
\\Dar~x+y=10\\
\\ \Rightarrow 4+y+y=10 \\
\\ 2y=10-4\\
\\ y=6:2\\
\\ \Rightarrow \boxed{y=3}\\
\\ si~x=4+3=7\\
\\ \Rightarrow \boxed{x=7}\\
\\ \\
\\ Verificare:\\
\\ 73-37=36[/tex]