You can put this solution on YOUR website! From
1/x + 1/y = 5
2/x + 3/y = 13
double the first one and subtract it from the second and get
2/x + 3/y = 13
-(2/x + 2/y = 10)
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1/y = 3
so that y = 1/3 and then
1/x + 3 = 5
1/x = 2
x = 1/2
(1/2 , 1/3)