[tex]\it \overline{x,y} + \overline{y,x} =6,6|_{\cdot10} \Rightarrow \overline{xy}+ \overline{yx}=66 \Rightarrow 10x+y+10y+x=66 \Rightarrow
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\Rightarrow 11x+11y=66 \Rightarrow 11(x+y)=66|_{:11} \Rightarrow x+y=6 \ \ \ \ (1)[/tex]
[tex]\it 6 = 1+5=2+4=3+3=4+2=5+1 \ \ \ \ (2)
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(1),\ \ (2) \Rightarrow (x,\ y) \in \{ (1,\ 5),\ (2,\ 4),\ (3,\ 3),\ (4,\ 2),\ (5,\ 1)\}
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