Solve the system by substitution: $$y = 2x + 1$
$x + y = 7$$
x=2,y=5x = 2, y = 5x=2,y=5
x=3,y=7x = 3, y = 7x=3,y=7
x=1,y=3x = 1, y = 3x=1,y=3
x=4,y=9x = 4, y = 9x=4,y=9