Respuesta :

naǫ
[tex]3x+y=19 \\ x+3y=1 \\ \\ \hbox{add the sides of the equations:} \\ 3x+x+y+3y=19+1 \\ 4x+4y=20 \\ \\ \hbox{divide both sides by 2:} \\ 2x+2y=10[/tex]

The answer is d. 10.