Đặt: \(\frac{x}{5}=\frac{y}{3}=k\)
\(\Rightarrow\left\{{}\begin{matrix}x=5k\\y=3k\end{matrix}\right.\)
Ta có: x2 - y2 = 16
=> (5k)2 - (3k)2 = 16
=> 25k2 - 9k2 = 16
=> k2. (25 - 9) = 16
=> k2 . 16 = 16
=> k2 = 1
=> k = 1 hoặc k = -1
Có: \(\left[{}\begin{matrix}\left\{{}\begin{matrix}x=5k=5.1=5\\y=3k=3.1=3\end{matrix}\right.\\\left\{{}\begin{matrix}x=5k=5.\left(-1\right)=-5\\y=3k=3.\left(-1\right)=-3\end{matrix}\right.\end{matrix}\right.\)