Ta có : \(\left(x-4\right)\left(y-4\right)=416\)
=> \(x=\frac{416}{y-4}+4\)
=> \(y-4\inƯ_{\left(416\right)}\)
=> \(y-4\in\left\{416,208,104,52,32,26,16,13,8,4,2,1,-....\right\}\)
=> \(y\in\left\{420,212,108,56,36,30,20,17,12,8,6,5,-....\right\}\)
=> \(x\in\left\{1,2,4,8,13,.....\right\}\)
Vậy ....