The given equations are
x + y = 3
3x - y = 1
From the second equation,
y = 3x - 1
Substituting y = 3x - 1 into the equation, we have
x + 3x - 1 = 3
x + 3x = 3 + 1
4x = 4
x = 4/4
x = 1
Substituting x = 1 into y = 3x - 1, we have
y = 3 * 1 - 1 = 3 - 1
y = 2
The solution is (1, 2)