Answer:
 (x, y) = (2, 1)
Explanation:
The x-coefficients are opposites of each other, so the x variable will be eliminated if the two equations are added.
 (x +3y) +(-x -y) = (5) +(-3)
 2y = 2
 y = 1
Substituting into the first equation gives ...
 x +3(1) = 5
 x = 2 . . . . . . . subtract 3
The solution is (x, y) = (2, 1).