[tex]\begin{cases} \frac{1}{2}x + \frac{1}{2}y =4\ \ \ \ | \ multiply\ both\ sides\ by\ 2 \\3x -2y =\frac{5}{4}\ \ \ | \ multiply\ both\ sides\ by\ 4 \end{cases}\\\\\begin{cases} x + y =8\ \ \ | \ multiply\ both\ sides\ by\ 8 \\12x -8y =5 \end{cases} \\\\\begin{cases} 8x + 8y =64 \\12x -8y =5 \end{cases} \\+-------\\ 20x=69 \ \ / :20[/tex]
[tex]x=\frac{69}{20}=3\frac{9}{20}\\\\\\x+y=8\\\\3\frac{ 9}{20}+y=8 \\\\y=8-3\frac{9}{20}\\\\y=4\frac{11}{20}[/tex]
[tex]Answer : \ \begin{cases} x= 3\frac{9}{20}\\ y=4\frac{11}{20} \end{cases}[/tex]