Answer :
[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.
The answer is d. 10.