$\begin{cases}\\8x-7y =5\\\\\\12x+13y =8 \\\\\end{cases}$
$\to$
$\begin{cases}\\24x-21y =15\\\\\\24x+26y =16 \\\\\end{cases}$
$\to$
$\begin{cases}\\-47y = -1 \\\\\\24x+26y =16 \\\\\end{cases}$
$\to$
$\begin{cases}\\y = \dfrac{1}{47} \\\\\\24x+26y =16 \\\\\end{cases}$
$\to$
$\begin{cases}\\y = \dfrac{1}{47} \\\\\\24x+ \dfrac{26}{47} =16 \\\\\end{cases}$
$\to$
$\begin{cases}\\y = \dfrac{1}{47} \\\\\\ x = \dfrac{121}{188} \\\\\end{cases}$
Vậy $(x;y) = ( \dfrac{121}{188} ; \dfrac{1}{47})$
